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http://rosettacode.org/wiki/Four_is_magic
|
Four is magic
|
Task
Write a subroutine, function, whatever it may be called in your language, that takes an integer number and returns an English text sequence starting with the English cardinal representation of that integer, the word 'is' and then the English cardinal representation of the count of characters that made up the first word, followed by a comma.
Continue the sequence by using the previous count word as the first word of the next phrase, append 'is' and the cardinal count of the letters in that word.
Continue until you reach four. Since four has four characters, finish by adding the words 'four is magic' and a period. All integers will eventually wind up at four.
For instance, suppose your are given the integer 3. Convert 3 to Three, add is , then the cardinal character count of three, or five, with a comma to separate if from the next phrase. Continue the sequence five is four, (five has four letters), and finally, four is magic.
Three is five, five is four, four is magic.
For reference, here are outputs for 0 through 9.
Zero is four, four is magic.
One is three, three is five, five is four, four is magic.
Two is three, three is five, five is four, four is magic.
Three is five, five is four, four is magic.
Four is magic.
Five is four, four is magic.
Six is three, three is five, five is four, four is magic.
Seven is five, five is four, four is magic.
Eight is five, five is four, four is magic.
Nine is four, four is magic.
Some task guidelines
You may assume the input will only contain integer numbers.
Cardinal numbers between 20 and 100 may use either hyphens or spaces as word separators but they must use a word separator. (23 is twenty three or twenty-three not twentythree.)
Cardinal number conversions should follow the English short scale. (billion is 1e9, trillion is 1e12, etc.)
Cardinal numbers should not include commas. (20140 is twenty thousand one hundred forty not twenty thousand, one hundred forty.)
When converted to a string, 100 should be one hundred, not a hundred or hundred, 1000 should be one thousand, not a thousand or thousand.
When converted to a string, there should be no and in the cardinal string. 130 should be one hundred thirty not one hundred and thirty.
When counting characters, count all of the characters in the cardinal number including spaces and hyphens. One hundred fifty-one should be 21 not 18.
The output should follow the format "N is K, K is M, M is ... four is magic." (unless the input is 4, in which case the output should simply be "four is magic.")
The output can either be the return value from the function, or be displayed from within the function.
You are encouraged, though not mandated to use proper sentence capitalization.
You may optionally support negative numbers. -7 is negative seven.
Show the output here for a small representative sample of values, at least 5 but no more than 25. You are free to choose which which numbers to use for output demonstration.
You can choose to use a library, (module, external routine, whatever) to do the cardinal conversions as long as the code is easily and freely available to the public.
If you roll your own, make the routine accept at minimum any integer from 0 up to 999999. If you use a pre-made library, support at least up to unsigned 64 bit integers. (or the largest integer supported in your language if it is less.)
Four is magic is a popular code-golf task. This is not code golf. Write legible, idiomatic and well formatted code.
Related tasks
Four is the number of_letters in the ...
Look-and-say sequence
Number names
Self-describing numbers
Summarize and say sequence
Spelling of ordinal numbers
De Bruijn sequences
|
#Swift
|
Swift
|
import Foundation
func fourIsMagic(_ number: NSNumber) -> String {
let formatter = NumberFormatter()
formatter.numberStyle = .spellOut
formatter.locale = Locale(identifier: "en_EN")
var result: [String] = []
var numberString = formatter.string(from: number)!
result.append(numberString.capitalized)
while numberString != "four" {
numberString = formatter.string(from: NSNumber(value: numberString.count))!
result.append(contentsOf: [" is ", numberString, ", ", numberString])
}
result.append(" is magic.")
return result.joined()
}
for testInput in [23, 1000000000, 20140, 100, 130, 151, -7] {
print(fourIsMagic(testInput as NSNumber))
}
|
http://rosettacode.org/wiki/Four_is_magic
|
Four is magic
|
Task
Write a subroutine, function, whatever it may be called in your language, that takes an integer number and returns an English text sequence starting with the English cardinal representation of that integer, the word 'is' and then the English cardinal representation of the count of characters that made up the first word, followed by a comma.
Continue the sequence by using the previous count word as the first word of the next phrase, append 'is' and the cardinal count of the letters in that word.
Continue until you reach four. Since four has four characters, finish by adding the words 'four is magic' and a period. All integers will eventually wind up at four.
For instance, suppose your are given the integer 3. Convert 3 to Three, add is , then the cardinal character count of three, or five, with a comma to separate if from the next phrase. Continue the sequence five is four, (five has four letters), and finally, four is magic.
Three is five, five is four, four is magic.
For reference, here are outputs for 0 through 9.
Zero is four, four is magic.
One is three, three is five, five is four, four is magic.
Two is three, three is five, five is four, four is magic.
Three is five, five is four, four is magic.
Four is magic.
Five is four, four is magic.
Six is three, three is five, five is four, four is magic.
Seven is five, five is four, four is magic.
Eight is five, five is four, four is magic.
Nine is four, four is magic.
Some task guidelines
You may assume the input will only contain integer numbers.
Cardinal numbers between 20 and 100 may use either hyphens or spaces as word separators but they must use a word separator. (23 is twenty three or twenty-three not twentythree.)
Cardinal number conversions should follow the English short scale. (billion is 1e9, trillion is 1e12, etc.)
Cardinal numbers should not include commas. (20140 is twenty thousand one hundred forty not twenty thousand, one hundred forty.)
When converted to a string, 100 should be one hundred, not a hundred or hundred, 1000 should be one thousand, not a thousand or thousand.
When converted to a string, there should be no and in the cardinal string. 130 should be one hundred thirty not one hundred and thirty.
When counting characters, count all of the characters in the cardinal number including spaces and hyphens. One hundred fifty-one should be 21 not 18.
The output should follow the format "N is K, K is M, M is ... four is magic." (unless the input is 4, in which case the output should simply be "four is magic.")
The output can either be the return value from the function, or be displayed from within the function.
You are encouraged, though not mandated to use proper sentence capitalization.
You may optionally support negative numbers. -7 is negative seven.
Show the output here for a small representative sample of values, at least 5 but no more than 25. You are free to choose which which numbers to use for output demonstration.
You can choose to use a library, (module, external routine, whatever) to do the cardinal conversions as long as the code is easily and freely available to the public.
If you roll your own, make the routine accept at minimum any integer from 0 up to 999999. If you use a pre-made library, support at least up to unsigned 64 bit integers. (or the largest integer supported in your language if it is less.)
Four is magic is a popular code-golf task. This is not code golf. Write legible, idiomatic and well formatted code.
Related tasks
Four is the number of_letters in the ...
Look-and-say sequence
Number names
Self-describing numbers
Summarize and say sequence
Spelling of ordinal numbers
De Bruijn sequences
|
#UNIX_Shell
|
UNIX Shell
|
#!/usr/bin/env bash
name_of() {
# return the English name for a numeric value
local -i n=$1
if (( n < 0 )); then
printf 'negative %s\n' "$(name_of $(( -n )))"
return 0
fi
# Names for numbers that fit in a bash integer
local -A names=([0]=zero [1]=one [2]=two [3]=three [4]=four [5]=five
[6]=six [7]=seven [8]=eight [9]=nine [10]=ten [11]=eleven
[12]=twelve [13]=thirteen [14]=fourteen [15]=fifteen
[16]=sixteen [17]=seventeen [18]=eighteen [19]=nineteen
[20]=twenty [30]=thirty [40]=forty [50]=fifty [60]=sixty
[70]=seventy [80]=eighty [90]=ninety [100]=hundred
[1000]=thousand [1000000]=million [1000000000]=billion
[1000000000000]=trillion [1000000000000000]=quadrillion
[1000000000000000000]=quintillion)
# The powers of 10 above 10, in descending order
local powers_of_10=($(printf '%s\n' "${!names[@]}" | sort -nr | grep '00$'))
# find the largest power of 10 that is smaller than n
local -i i=0
local -i p=${powers_of_10[i]}
while (( p > n && i < ${#powers_of_10[@]}-1 )); do
i=i+1
p=${powers_of_10[$i]}
done
# if we found one, split on it and construct quotient 'name' remainder
if (( n >= p )); then
local -i quotient=n/p
local -i remainder=n%p
local remname=
if (( remainder > 0 )); then
remname=$(name_of $remainder)
fi
printf '%s %s\n' "$(name_of $quotient)" "${names[$p]}${remname:+ $remname}"
elif (( n > 20 )); then
# things are a little different under 100, since the multiples of
# 10 have their own names
local -i remainder=n%10
local -i tens=n-remainder
local remname=
if (( remainder > 0 )); then
remname=-$(name_of $remainder)
fi
printf '%s\n' "${names[$tens]}${remname:+$remname}"
else
printf '%s\n' "${names[$n]}"
fi
return 0
}
# Convert numbers into the length of their names
# Display the series of values in name form until
# the length turns into four; then terminate with "four is magic."
# Again, takes a second argument, this time a prefix, to
# facilitate tail recursion.
four_is_magic() {
local -i n=$1
local prefix=$2
local name=$(name_of $n)
# capitalize the first entry
if [[ -z $prefix ]]; then
name=${name^}
fi
# Stop at 4, otherwise count the length of the name and recurse
if (( $n == 4 )); then
printf '%s%s is magic.\n' "${prefix:+$prefix, }" "$name"
else
local -i len=${#name}
four_is_magic "$len" "${prefix:+$prefix, }$name is $(name_of $len)"
fi
}
|
http://rosettacode.org/wiki/Floyd%27s_triangle
|
Floyd's triangle
|
Floyd's triangle lists the natural numbers in a right triangle aligned to the left where
the first row is 1 (unity)
successive rows start towards the left with the next number followed by successive naturals listing one more number than the line above.
The first few lines of a Floyd triangle looks like this:
1
2 3
4 5 6
7 8 9 10
11 12 13 14 15
Task
Write a program to generate and display here the first n lines of a Floyd triangle.
(Use n=5 and n=14 rows).
Ensure that when displayed in a mono-space font, the numbers line up in vertical columns as shown and that only one space separates numbers of the last row.
|
#BCPL
|
BCPL
|
get "libhdr"
let width(n) = n<10 -> 1, 1 + width(n/10)
let floyd(rows) be
$( let maxno = rows * (rows+1)/2
let num = 1
for r = 1 to rows
$( for c = 1 to r
$( writed(num, 1 + width(maxno-rows+c))
num := num + 1
$)
wrch('*N')
$)
$)
let start() be
$( floyd(5)
wrch('*N')
floyd(14)
$)
|
http://rosettacode.org/wiki/Floyd%27s_triangle
|
Floyd's triangle
|
Floyd's triangle lists the natural numbers in a right triangle aligned to the left where
the first row is 1 (unity)
successive rows start towards the left with the next number followed by successive naturals listing one more number than the line above.
The first few lines of a Floyd triangle looks like this:
1
2 3
4 5 6
7 8 9 10
11 12 13 14 15
Task
Write a program to generate and display here the first n lines of a Floyd triangle.
(Use n=5 and n=14 rows).
Ensure that when displayed in a mono-space font, the numbers line up in vertical columns as shown and that only one space separates numbers of the last row.
|
#Befunge
|
Befunge
|
0" :seniL">:#,_&>:!#@_55+,:00p::1+*2/1v
vv+1:\-1p01g5-\g00<v`*9"o"\+`"c"\`9:::_
$>>\:::9`\"c"`+\9v:>>+00g1-:00p5p1-00g^
<v\*84-\g01+`*"o"<^<<p00:+1\+1/2*+1:::\
^>:#\1#,-#:\_$$.\:#^_$$>>1+\1-55+,:!#@_
|
http://rosettacode.org/wiki/Floyd-Warshall_algorithm
|
Floyd-Warshall algorithm
|
The Floyd–Warshall algorithm is an algorithm for finding shortest paths in a weighted graph with positive or negative edge weights.
Task
Find the lengths of the shortest paths between all pairs of vertices of the given directed graph. Your code may assume that the input has already been checked for loops, parallel edges and negative cycles.
Print the pair, the distance and (optionally) the path.
Example
pair dist path
1 -> 2 -1 1 -> 3 -> 4 -> 2
1 -> 3 -2 1 -> 3
1 -> 4 0 1 -> 3 -> 4
2 -> 1 4 2 -> 1
2 -> 3 2 2 -> 1 -> 3
2 -> 4 4 2 -> 1 -> 3 -> 4
3 -> 1 5 3 -> 4 -> 2 -> 1
3 -> 2 1 3 -> 4 -> 2
3 -> 4 2 3 -> 4
4 -> 1 3 4 -> 2 -> 1
4 -> 2 -1 4 -> 2
4 -> 3 1 4 -> 2 -> 1 -> 3
See also
Floyd-Warshall Algorithm - step by step guide (youtube)
|
#Icon
|
Icon
|
#
# Floyd-Warshall algorithm.
#
# See https://en.wikipedia.org/w/index.php?title=Floyd%E2%80%93Warshall_algorithm&oldid=1082310013
#
record fw_results (n, distance, next_vertex)
link array
link numbers
link printf
procedure main ()
local example_graph
local fw
local u, v
example_graph := [[1, -2.0, 3],
[3, +2.0, 4],
[4, -1.0, 2],
[2, +4.0, 1],
[2, +3.0, 3]]
fw := floyd_warshall (example_graph)
printf (" pair distance path\n")
printf ("-------------------------------------\n")
every u := 1 to fw.n do {
every v := 1 to fw.n do {
if u ~= v then {
printf (" %d -> %d %4s %s\n", u, v,
string (ref_array (fw.distance, u, v)),
path_to_string (find_path (fw.next_vertex, u, v)))
}
}
}
end
procedure floyd_warshall (edges)
local n, distance, next_vertex
local e
local i, j, k
local dist_ij, dist_ik, dist_kj, dist_ikj
n := max_vertex (edges)
distance := create_array ([1, 1], [n, n], &null)
next_vertex := create_array ([1, 1], [n, n], &null)
# Initialization.
every e := !edges do {
ref_array (distance, e[1], e[3]) := e[2]
ref_array (next_vertex, e[1], e[3]) := e[3]
}
every i := 1 to n do {
ref_array (distance, i, i) := 0.0 # Distance to self = 0.
ref_array (next_vertex, i, i) := i
}
# Perform the algorithm. Here &null will play the role of
# "infinity": "\" means a value is finite, "/" that it is infinite.
every k := 1 to n do {
every i := 1 to n do {
every j := 1 to n do {
dist_ij := ref_array (distance, i, j)
dist_ik := ref_array (distance, i, k)
dist_kj := ref_array (distance, k, j)
if \dist_ik & \dist_kj then {
dist_ikj := dist_ik + dist_kj
if /dist_ij | dist_ikj < dist_ij then {
ref_array (distance, i, j) := dist_ikj
ref_array (next_vertex, i, j) :=
ref_array (next_vertex, i, k)
}
}
}
}
}
return fw_results (n, distance, next_vertex)
end
procedure find_path (next_vertex, u, v)
local path
if / (ref_array (next_vertex, u, v)) then {
path := []
} else {
path := [u]
while u ~= v do {
u := ref_array (next_vertex, u, v)
put (path, u)
}
}
return path
end
procedure path_to_string (path)
local s
if *path = 0 then {
s := ""
} else {
s := string (path[1])
every s ||:= (" -> " || !path[2 : 0])
}
return s
end
procedure max_vertex (edges)
local e
local m
*edges = 0 & stop ("no edges")
m := 1
every e := !edges do m := max (m, e[1], e[3])
return m
end
|
http://rosettacode.org/wiki/Function_definition
|
Function definition
|
A function is a body of code that returns a value.
The value returned may depend on arguments provided to the function.
Task
Write a definition of a function called "multiply" that takes two arguments and returns their product.
(Argument types should be chosen so as not to distract from showing how functions are created and values returned).
Related task
Function prototype
|
#Raven
|
Raven
|
define multiply use a, b
a b *
|
http://rosettacode.org/wiki/Function_definition
|
Function definition
|
A function is a body of code that returns a value.
The value returned may depend on arguments provided to the function.
Task
Write a definition of a function called "multiply" that takes two arguments and returns their product.
(Argument types should be chosen so as not to distract from showing how functions are created and values returned).
Related task
Function prototype
|
#REALbasic
|
REALbasic
|
Function Multiply(a As Integer, b As Integer) As Integer
Return a * b
End Function
|
http://rosettacode.org/wiki/Forward_difference
|
Forward difference
|
Task
Provide code that produces a list of numbers which is the nth order forward difference, given a non-negative integer (specifying the order) and a list of numbers.
The first-order forward difference of a list of numbers A is a new list B, where Bn = An+1 - An.
List B should have one fewer element as a result.
The second-order forward difference of A will be:
tdefmodule Diff do
def forward(arr,i\\1) do
forward(arr,[],i)
end
def forward([_|[]],diffs,i) do
if i == 1 do
IO.inspect diffs
else
forward(diffs,[],i-1)
end
end
def forward([val1|[val2|vals]],diffs,i) do
forward([val2|vals],diffs++[val2-val1],i)
end
end
The same as the first-order forward difference of B.
That new list will have two fewer elements than A and one less than B.
The goal of this task is to repeat this process up to the desired order.
For a more formal description, see the related Mathworld article.
Algorithmic options
Iterate through all previous forward differences and re-calculate a new array each time.
Use this formula (from Wikipedia):
Δ
n
[
f
]
(
x
)
=
∑
k
=
0
n
(
n
k
)
(
−
1
)
n
−
k
f
(
x
+
k
)
{\displaystyle \Delta ^{n}[f](x)=\sum _{k=0}^{n}{n \choose k}(-1)^{n-k}f(x+k)}
(Pascal's Triangle may be useful for this option.)
|
#Lua
|
Lua
|
function dif(a, b, ...)
if(b) then return b-a, dif(b, ...) end
end
function dift(t) return {dif(unpack(t))} end
print(unpack(dift{1,3,6,10,15}))
|
http://rosettacode.org/wiki/Hello_world/Text
|
Hello world/Text
|
Hello world/Text is part of Short Circuit's Console Program Basics selection.
Task
Display the string Hello world! on a text console.
Related tasks
Hello world/Graphical
Hello world/Line Printer
Hello world/Newbie
Hello world/Newline omission
Hello world/Standard error
Hello world/Web server
|
#XSLT
|
XSLT
|
<xsl:text>Hello world!
</xsl:text>
|
http://rosettacode.org/wiki/Hello_world/Text
|
Hello world/Text
|
Hello world/Text is part of Short Circuit's Console Program Basics selection.
Task
Display the string Hello world! on a text console.
Related tasks
Hello world/Graphical
Hello world/Line Printer
Hello world/Newbie
Hello world/Newline omission
Hello world/Standard error
Hello world/Web server
|
#Yabasic
|
Yabasic
|
print "Hello world!"
|
http://rosettacode.org/wiki/Formatted_numeric_output
|
Formatted numeric output
|
Task
Express a number in decimal as a fixed-length string with leading zeros.
For example, the number 7.125 could be expressed as 00007.125.
|
#PicoLisp
|
PicoLisp
|
(pad 9 (format 7125 3))
(pad 9 (format 7125 3 ",")) # European format
|
http://rosettacode.org/wiki/Formatted_numeric_output
|
Formatted numeric output
|
Task
Express a number in decimal as a fixed-length string with leading zeros.
For example, the number 7.125 could be expressed as 00007.125.
|
#PL.2FI
|
PL/I
|
put edit (X) (p'999999.V999'); /* Western format. */
put edit (X) (p'999999,V999'); /* In European format. */
|
http://rosettacode.org/wiki/Four_bit_adder
|
Four bit adder
|
Task
"Simulate" a four-bit adder.
This design can be realized using four 1-bit full adders.
Each of these 1-bit full adders can be built with two half adders and an or gate. ;
Finally a half adder can be made using an xor gate and an and gate.
The xor gate can be made using two nots, two ands and one or.
Not, or and and, the only allowed "gates" for the task, can be "imitated" by using the bitwise operators of your language.
If there is not a bit type in your language, to be sure that the not does not "invert" all the other bits of the basic type (e.g. a byte) we are not interested in, you can use an extra nand (and then not) with the constant 1 on one input.
Instead of optimizing and reducing the number of gates used for the final 4-bit adder, build it in the most straightforward way, connecting the other "constructive blocks", in turn made of "simpler" and "smaller" ones.
Schematics of the "constructive blocks"
(Xor gate with ANDs, ORs and NOTs)
(A half adder)
(A full adder)
(A 4-bit adder)
Solutions should try to be as descriptive as possible, making it as easy as possible to identify "connections" between higher-order "blocks".
It is not mandatory to replicate the syntax of higher-order blocks in the atomic "gate" blocks, i.e. basic "gate" operations can be performed as usual bitwise operations, or they can be "wrapped" in a block in order to expose the same syntax of higher-order blocks, at implementers' choice.
To test the implementation, show the sum of two four-bit numbers (in binary).
|
#MATLAB_.2F_Octave
|
MATLAB / Octave
|
function [S,v] = fourBitAdder(input1,input2)
%Make sure that only 4-Bit numbers are being added. This assumes that
%if input1 and input2 are a vector of multiple decimal numbers, then
%the binary form of these vectors are an n by 4 matrix.
assert((size(input1,2) == 4) && (size(input2,2) == 4),'This will only work on 4-Bit Numbers');
%Converts MATLAB binary strings to matricies of 1 and 0
function mat = binStr2Mat(binStr)
mat = zeros(size(binStr));
for i = (1:numel(binStr))
mat(i) = str2double(binStr(i));
end
end
%XOR decleration
function AxorB = xor(A,B)
AxorB = or(and(A,not(B)),and(B,not(A)));
end
%Half-Adder decleration
function [S,C] = halfAdder(A,B)
S = xor(A,B);
C = and(A,B);
end
%Full-Adder decleration
function [S,Co] = fullAdder(A,B,Ci)
[SAdder1,CAdder1] = halfAdder(Ci,A);
[S,CAdder2] = halfAdder(SAdder1,B);
Co = or(CAdder1,CAdder2);
end
%The rest of this code is the 4-bit adder
binStrFlag = false; %A flag to determine if the original input was a binary string
%If either of the inputs was a binary string, convert it to a matrix of
%1's and 0's.
if ischar(input1)
input1 = binStr2Mat(input1);
binStrFlag = true;
end
if ischar(input2)
input2 = binStr2Mat(input2);
binStrFlag = true;
end
%This does the addition
S = zeros(size(input1));
[S(:,4),Co] = fullAdder(input1(:,4),input2(:,4),0);
[S(:,3),Co] = fullAdder(input1(:,3),input2(:,3),Co);
[S(:,2),Co] = fullAdder(input1(:,2),input2(:,2),Co);
[S(:,1),v] = fullAdder(input1(:,1),input2(:,1),Co);
%If the original inputs were binary strings, convert the output of the
%4-bit adder to a binary string with the same formatting as the
%original binary strings.
if binStrFlag
S = num2str(S);
v = num2str(v);
end
end %fourBitAdder
|
http://rosettacode.org/wiki/Fivenum
|
Fivenum
|
Many big data or scientific programs use boxplots to show distributions of data. In addition, sometimes saving large arrays for boxplots can be impractical and use extreme amounts of RAM. It can be useful to save large arrays as arrays with five numbers to save memory.
For example, the R programming language implements Tukey's five-number summary as the fivenum function.
Task
Given an array of numbers, compute the five-number summary.
Note
While these five numbers can be used to draw a boxplot, statistical packages will typically need extra data.
Moreover, while there is a consensus about the "box" of the boxplot, there are variations among statistical packages for the whiskers.
|
#Arturo
|
Arturo
|
fivenum: function [lst][
lst: sort lst
m: (size lst)/2
lowerEnd: (odd? size lst)? -> m -> m-1
return @[
first lst
median slice lst 0 lowerEnd
median slice lst 0 dec size lst
median slice lst m dec size lst
last lst
]
]
lists: @[
@[15.0, 6.0, 42.0, 41.0, 7.0, 36.0, 49.0, 40.0, 39.0, 47.0, 43.0],
@[36.0, 40.0, 7.0, 39.0, 41.0, 15.0],
@[0.14082834, 0.09748790, 1.73131507, 0.87636009,0-1.95059594,
0.73438555,0-0.03035726, 1.46675970,0-0.74621349,0-0.72588772,
0.63905160, 0.61501527,0-0.98983780,0-1.00447874,0-0.62759469,
0.66206163, 1.04312009,0-0.10305385, 0.75775634, 0.32566578]
]
loop lists 'l [
print [l "->"]
print [fivenum l]
print ""
]
|
http://rosettacode.org/wiki/Forest_fire
|
Forest fire
|
This page uses content from Wikipedia. The original article was at Forest-fire model. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
Task
Implement the Drossel and Schwabl definition of the forest-fire model.
It is basically a 2D cellular automaton where each cell can be in three distinct states (empty, tree and burning) and evolves according to the following rules (as given by Wikipedia)
A burning cell turns into an empty cell
A tree will burn if at least one neighbor is burning
A tree ignites with probability f even if no neighbor is burning
An empty space fills with a tree with probability p
Neighborhood is the Moore neighborhood; boundary conditions are so that on the boundary the cells are always empty ("fixed" boundary condition).
At the beginning, populate the lattice with empty and tree cells according to a specific probability (e.g. a cell has the probability 0.5 to be a tree). Then, let the system evolve.
Task's requirements do not include graphical display or the ability to change parameters (probabilities p and f ) through a graphical or command line interface.
Related tasks
See Conway's Game of Life
See Wireworld.
|
#Common_Lisp
|
Common Lisp
|
(defvar *dims* '(10 10))
(defvar *prob-t* 0.5)
(defvar *prob-f* 0.1)
(defvar *prob-p* 0.01)
(defmacro with-gensyms (names &body body)
`(let ,(mapcar (lambda (n) (list n '(gensym))) names)
,@body))
(defmacro traverse-grid (grid rowvar colvar (&rest after-cols) &body body)
(with-gensyms (dims rows cols)
`(let* ((,dims (array-dimensions ,grid))
(,rows (car ,dims))
(,cols (cadr ,dims)))
(dotimes (,rowvar ,rows ,grid)
(dotimes (,colvar ,cols ,after-cols)
,@body)))))
(defun make-new-forest (&optional (dims *dims*))
(let ((forest (make-array dims :element-type 'symbol :initial-element 'void)))
(traverse-grid forest row col nil
(if (<= (random 1.0) *prob-t*)
(setf (aref forest row col) 'tree)))))
(defun print-forest (forest)
(traverse-grid forest row col (terpri)
(ecase (aref forest row col)
((void) (write-char #\space))
((tree) (write-char #\T))
((fire) (write-char #\#))))
(values))
(defvar *neighboring* '((-1 . -1) (-1 . 0) (-1 . 1)
(0 . -1) (0 . 1)
(1 . -1) (1 . 0) (1 . 1)))
(defun neighbors (forest row col)
(loop for n in *neighboring*
for nrow = (+ row (car n))
for ncol = (+ col (cdr n))
when (array-in-bounds-p forest nrow ncol)
collect (aref forest nrow ncol)))
(defun evolve-tree (forest row col)
(let ((tree (aref forest row col)))
(cond ((eq tree 'fire) ;; if the tree was on fire, it's dead Jim
'void)
((and (eq tree 'tree) ;; if a neighbor is on fire, it's on fire too
(find 'fire (neighbors forest row col) :test #'eq))
'fire)
((and (eq tree 'tree) ;; random chance of fire happening
(<= (random 1.0) *prob-f*))
'fire)
((and (eq tree 'void) ;; random chance of empty space becoming a tree
(<= (random 1.0) *prob-p*))
'tree)
(t tree))))
(defun evolve-forest (forest)
(let* ((dims (array-dimensions forest))
(new (make-array dims :element-type 'symbol :initial-element 'void)))
(traverse-grid forest row col nil
(setf (aref new row col) (evolve-tree forest row col)))
new))
(defun simulate (forest n &optional (print-all t))
(format t "------ Initial forest ------~%")
(print-forest forest)
(dotimes (i n)
(setf forest (evolve-forest forest))
(when print-all
(progn (format t "~%------ Generation ~d ------~%" (1+ i))
(print-forest forest)))))
|
http://rosettacode.org/wiki/First_class_environments
|
First class environments
|
According to Wikipedia, "In computing, a first-class object ... is an entity that can be constructed at run-time, passed as a parameter, returned from a subroutine, or assigned into a variable".
Often this term is used in the context of "first class functions". In an analogous way, a programming language may support "first class environments".
The environment is minimally, the set of variables accessible to a statement being executed. Change the environments and the same statement could produce different results when executed.
Often an environment is captured in a closure, which encapsulates a function together with an environment. That environment, however, is not first-class, as it cannot be created, passed etc. independently from the function's code.
Therefore, a first class environment is a set of variable bindings which can be constructed at run-time, passed as a parameter, returned from a subroutine, or assigned into a variable. It is like a closure without code. A statement must be able to be executed within a stored first class environment and act according to the environment variable values stored within.
Task
Build a dozen environments, and a single piece of code to be run repeatedly in each of these environments.
Each environment contains the bindings for two variables:
a value in the Hailstone sequence, and
a count which is incremented until the value drops to 1.
The initial hailstone values are 1 through 12, and the count in each environment is zero.
When the code runs, it calculates the next hailstone step in the current environment (unless the value is already 1) and counts the steps. Then it prints the current value in a tabular form.
When all hailstone values dropped to 1, processing stops, and the total number of hailstone steps for each environment is printed.
|
#BBC_BASIC
|
BBC BASIC
|
DIM @environ$(12)
@% = 4 : REM Column width
REM Initialise:
FOR E% = 1 TO 12
PROCsetenvironment(@environ$(E%))
seq% = E%
cnt% = 0
@environ$(E%) = FNgetenvironment
NEXT
REM Run hailstone sequences:
REPEAT
T% = 0
FOR E% = 1 TO 12
PROCsetenvironment(@environ$(E%))
PRINT seq% ;
IF seq% <> 1 THEN
T% += 1
cnt% += 1
IF seq% AND 1 seq% = 3 * seq% + 1 ELSE seq% DIV= 2
ENDIF
@environ$(E%) = FNgetenvironment
NEXT
PRINT
UNTIL T% = 0
REM Print counts:
PRINT "Counts:"
FOR E% = 1 TO 12
PROCsetenvironment(@environ$(E%))
PRINT cnt% ;
@environ$(E%) = FNgetenvironment
NEXT
PRINT
END
DEF FNgetenvironment
LOCAL e$ : e$ = STRING$(216, CHR$0)
SYS "RtlMoveMemory", !^e$, ^@%+108, 216
= e$
DEF PROCsetenvironment(e$)
IF LEN(e$) < 216 e$ = STRING$(216, CHR$0)
SYS "RtlMoveMemory", ^@%+108, !^e$, 216
ENDPROC
|
http://rosettacode.org/wiki/Flatten_a_list
|
Flatten a list
|
Task
Write a function to flatten the nesting in an arbitrary list of values.
Your program should work on the equivalent of this list:
[[1], 2, [[3, 4], 5], [[[]]], [[[6]]], 7, 8, []]
Where the correct result would be the list:
[1, 2, 3, 4, 5, 6, 7, 8]
Related task
Tree traversal
|
#Brat
|
Brat
|
array.prototype.flatten = {
true? my.empty?
{ [] }
{ true? my.first.array?
{ my.first.flatten + my.rest.flatten }
{ [my.first] + my.rest.flatten }
}
}
list = [[1], 2, [[3,4], 5], [[[]]], [[[6]]], 7, 8, []]
p "List: #{list}"
p "Flattened: #{list.flatten}"
|
http://rosettacode.org/wiki/Flipping_bits_game
|
Flipping bits game
|
The game
Given an N×N square array of zeroes or ones in an initial configuration, and a target configuration of zeroes and ones.
The game is to transform one to the other in as few moves as possible by inverting whole numbered rows or whole lettered
columns at once (as one move).
In an inversion. any 1 becomes 0, and any 0 becomes 1 for that whole row or column.
Task
Create a program to score for the Flipping bits game.
The game should create an original random target configuration and a starting configuration.
Ensure that the starting position is never the target position.
The target position must be guaranteed as reachable from the starting position. (One possible way to do this is to generate the start position by legal flips from a random target position. The flips will always be reversible back to the target from the given start position).
The number of moves taken so far should be shown.
Show an example of a short game here, on this page, for a 3×3 array of bits.
|
#J
|
J
|
start=:3 :0
Moves=:0
N=:i.y
Board=: ?2$~,~y
'fr fc'=. (2,y)$}.#:(+?&.<:@<:)2x^2*y
End=: fr~:fc~:"1 Board
Board;End
)
abc=:'abcdefghij'
move=:3 :0
fc=. N e.abc i. y ([-.-.)abc
fr=. N e._-.~_ "."0 abc-.~":y
Board=: fr~:fc~:"1 Board
smoutput (":Moves=:Moves++/fr,fc),' moves'
if. Board-:End do.
'yes'
else.
Board;End
end.
)
|
http://rosettacode.org/wiki/First_power_of_2_that_has_leading_decimal_digits_of_12
|
First power of 2 that has leading decimal digits of 12
|
(This task is taken from a Project Euler problem.)
(All numbers herein are expressed in base ten.)
27 = 128 and 7 is
the first power of 2 whose leading decimal digits are 12.
The next power of 2 whose leading decimal digits
are 12 is 80,
280 = 1208925819614629174706176.
Define p(L,n) to be the nth-smallest
value of j such that the base ten representation
of 2j begins with the digits of L .
So p(12, 1) = 7 and
p(12, 2) = 80
You are also given that:
p(123, 45) = 12710
Task
find:
p(12, 1)
p(12, 2)
p(123, 45)
p(123, 12345)
p(123, 678910)
display the results here, on this page.
|
#Delphi
|
Delphi
|
// First power of 2 that has specified leading decimal digits. Nigel Galloway: March 14th., 2021
let fG n g=let fN l=let l=10.0**(l-floor l) in l>=n && l<g in let f=log10 2.0 in seq{1..0x0FFFFFFF}|>Seq.filter(float>>(*)f>>fN)
printfn "p(23,1)->%d" (int(Seq.item 0 (fG 2.3 2.4)))
printfn "p(99,1)->%d" (int(Seq.item 0 (fG 9.9 10.0)))
printfn "p(12,1)->%d" (int(Seq.item 0 (fG 1.2 1.3)))
printfn "p(12,2)->%d" (int(Seq.item 1 (fG 1.2 1.3)))
printfn "p(123,45)->%d" (int(Seq.item 44 (fG 1.23 1.24)))
printfn "p(123,12345)->%d" (int(Seq.item 12344 (fG 1.23 1.24)))
printfn "p(123,678910)->%d" (int(Seq.item 678909 (fG 1.23 1.24)))
|
http://rosettacode.org/wiki/First-class_functions/Use_numbers_analogously
|
First-class functions/Use numbers analogously
|
In First-class functions, a language is showing how its manipulation of functions is similar to its manipulation of other types.
This tasks aim is to compare and contrast a language's implementation of first class functions, with its normal handling of numbers.
Write a program to create an ordered collection of a mixture of literally typed and expressions producing a real number, together with another ordered collection of their multiplicative inverses. Try and use the following pseudo-code to generate the numbers for the ordered collections:
x = 2.0
xi = 0.5
y = 4.0
yi = 0.25
z = x + y
zi = 1.0 / ( x + y )
Create a function multiplier, that given two numbers as arguments returns a function that when called with one argument, returns the result of multiplying the two arguments to the call to multiplier that created it and the argument in the call:
new_function = multiplier(n1,n2)
# where new_function(m) returns the result of n1 * n2 * m
Applying the multiplier of a number and its inverse from the two ordered collections of numbers in pairs, show that the result in each case is one.
Compare and contrast the resultant program with the corresponding entry in First-class functions. They should be close.
To paraphrase the task description: Do what was done before, but with numbers rather than functions
|
#Elena
|
Elena
|
import system'routines;
import extensions;
public program()
{
real x := 2.0r;
real xi := 0.5r;
real y := 4.0r;
real yi := 0.25r;
real z := x + y;
real zi := 1.0r / (x + y);
var numlist := new real[]{ x, y, z };
var numlisti := new real[]{ xi, yi, zi };
var multiplied := numlist.zipBy(numlisti, (n1,n2 => (m => n1 * n2 * m) )).toArray();
multiplied.forEach:(multiplier){ console.printLine(multiplier(0.5r)) }
}
|
http://rosettacode.org/wiki/First-class_functions/Use_numbers_analogously
|
First-class functions/Use numbers analogously
|
In First-class functions, a language is showing how its manipulation of functions is similar to its manipulation of other types.
This tasks aim is to compare and contrast a language's implementation of first class functions, with its normal handling of numbers.
Write a program to create an ordered collection of a mixture of literally typed and expressions producing a real number, together with another ordered collection of their multiplicative inverses. Try and use the following pseudo-code to generate the numbers for the ordered collections:
x = 2.0
xi = 0.5
y = 4.0
yi = 0.25
z = x + y
zi = 1.0 / ( x + y )
Create a function multiplier, that given two numbers as arguments returns a function that when called with one argument, returns the result of multiplying the two arguments to the call to multiplier that created it and the argument in the call:
new_function = multiplier(n1,n2)
# where new_function(m) returns the result of n1 * n2 * m
Applying the multiplier of a number and its inverse from the two ordered collections of numbers in pairs, show that the result in each case is one.
Compare and contrast the resultant program with the corresponding entry in First-class functions. They should be close.
To paraphrase the task description: Do what was done before, but with numbers rather than functions
|
#Erlang
|
Erlang
|
-module( first_class_functions_use_numbers ).
-export( [task/0] ).
task() ->
X = 2.0, Xi = 0.5, Y = 4.0, Yi = 0.25, Z = X + Y, Zi = 1.0 / (X + Y),
As = [X, Y, Z],
Bs = [Xi, Yi, Zi],
[io:fwrite( "Value: 2.5 Result: ~p~n", [(multiplier(A, B))(2.5)]) || {A, B} <- lists:zip(As, Bs)].
multiplier( N1, N2 ) -> fun(M) -> N1 * N2 * M end.
|
http://rosettacode.org/wiki/Flow-control_structures
|
Flow-control structures
|
Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
Document common flow-control structures.
One common example of a flow-control structure is the goto construct.
Note that Conditional Structures and Loop Structures have their own articles/categories.
Related tasks
Conditional Structures
Loop Structures
|
#Java
|
Java
|
switch (xx) {
case 1:
case 2:
/* 1 & 2 both come here... */
...
break;
case 4:
/* 4 comes here... */
...
break;
case 5:
/* 5 comes here... */
...
break;
default:
/* everything else */
break;
}
for (int i = 0; i < 10; ++i) {
...
if (some_condition) { break; }
...
}
_Time_: do {
for (int i = 0; i < 10; ++i) {
...
if (some_condition) { break _Time_; /* terminate the do-while loop */}
...
}
...
} while (thisCondition);
|
http://rosettacode.org/wiki/Flow-control_structures
|
Flow-control structures
|
Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
Document common flow-control structures.
One common example of a flow-control structure is the goto construct.
Note that Conditional Structures and Loop Structures have their own articles/categories.
Related tasks
Conditional Structures
Loop Structures
|
#JavaScript
|
JavaScript
|
$ jq -n '1, (2 | label $foo | debug | 3 | break $foo | debug), 4'
1
["DEBUG:",2]
4
|
http://rosettacode.org/wiki/Four_is_magic
|
Four is magic
|
Task
Write a subroutine, function, whatever it may be called in your language, that takes an integer number and returns an English text sequence starting with the English cardinal representation of that integer, the word 'is' and then the English cardinal representation of the count of characters that made up the first word, followed by a comma.
Continue the sequence by using the previous count word as the first word of the next phrase, append 'is' and the cardinal count of the letters in that word.
Continue until you reach four. Since four has four characters, finish by adding the words 'four is magic' and a period. All integers will eventually wind up at four.
For instance, suppose your are given the integer 3. Convert 3 to Three, add is , then the cardinal character count of three, or five, with a comma to separate if from the next phrase. Continue the sequence five is four, (five has four letters), and finally, four is magic.
Three is five, five is four, four is magic.
For reference, here are outputs for 0 through 9.
Zero is four, four is magic.
One is three, three is five, five is four, four is magic.
Two is three, three is five, five is four, four is magic.
Three is five, five is four, four is magic.
Four is magic.
Five is four, four is magic.
Six is three, three is five, five is four, four is magic.
Seven is five, five is four, four is magic.
Eight is five, five is four, four is magic.
Nine is four, four is magic.
Some task guidelines
You may assume the input will only contain integer numbers.
Cardinal numbers between 20 and 100 may use either hyphens or spaces as word separators but they must use a word separator. (23 is twenty three or twenty-three not twentythree.)
Cardinal number conversions should follow the English short scale. (billion is 1e9, trillion is 1e12, etc.)
Cardinal numbers should not include commas. (20140 is twenty thousand one hundred forty not twenty thousand, one hundred forty.)
When converted to a string, 100 should be one hundred, not a hundred or hundred, 1000 should be one thousand, not a thousand or thousand.
When converted to a string, there should be no and in the cardinal string. 130 should be one hundred thirty not one hundred and thirty.
When counting characters, count all of the characters in the cardinal number including spaces and hyphens. One hundred fifty-one should be 21 not 18.
The output should follow the format "N is K, K is M, M is ... four is magic." (unless the input is 4, in which case the output should simply be "four is magic.")
The output can either be the return value from the function, or be displayed from within the function.
You are encouraged, though not mandated to use proper sentence capitalization.
You may optionally support negative numbers. -7 is negative seven.
Show the output here for a small representative sample of values, at least 5 but no more than 25. You are free to choose which which numbers to use for output demonstration.
You can choose to use a library, (module, external routine, whatever) to do the cardinal conversions as long as the code is easily and freely available to the public.
If you roll your own, make the routine accept at minimum any integer from 0 up to 999999. If you use a pre-made library, support at least up to unsigned 64 bit integers. (or the largest integer supported in your language if it is less.)
Four is magic is a popular code-golf task. This is not code golf. Write legible, idiomatic and well formatted code.
Related tasks
Four is the number of_letters in the ...
Look-and-say sequence
Number names
Self-describing numbers
Summarize and say sequence
Spelling of ordinal numbers
De Bruijn sequences
|
#Vlang
|
Vlang
|
import math
fn main() {
for n in [i64(0), 4, 6, 11, 13, 75, 100, 337, -164,
math.max_i64,
] {
println(four_is_magic(n))
}
}
fn four_is_magic(nn i64) string {
mut n := nn
mut s := say(n)
s = s[..1].to_upper() + s[1..]
mut t := s
for n != 4 {
n = i64(s.len)
s = say(n)
t += " is " + s + ", " + s
}
t += " is magic."
return t
}
const small = ["zero", "one", "two", "three", "four", "five", "six",
"seven", "eight", "nine", "ten", "eleven", "twelve", "thirteen",
"fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen"]
const tens = ["", "", "twenty", "thirty", "forty",
"fifty", "sixty", "seventy", "eighty", "ninety"]
const illions = ["", " thousand", " million", " billion",
" trillion", " quadrillion", " quintillion"]
fn say(nn i64) string {
mut t := ''
mut n := nn
if n < 0 {
t = "negative "
// Note, for math.MinInt64 this leaves n negative.
n = -n
}
match true {
n < 20 {
t += small[n]
}
n < 100 {
t += tens[n/10]
s := n % 10
if s > 0 {
t += "-" + small[s]
}
}
n < 1000 {
t += small[n/100] + " hundred"
s := n % 100
if s > 0 {
t += " " + say(s)
}
}
else {
// work right-to-left
mut sx := ""
for i := 0; n > 0; i++ {
p := n % 1000
n /= 1000
if p > 0 {
mut ix := say(p) + illions[i]
if sx != "" {
ix += " " + sx
}
sx = ix
}
}
t += sx
}
}
return t
}
|
http://rosettacode.org/wiki/Four_is_magic
|
Four is magic
|
Task
Write a subroutine, function, whatever it may be called in your language, that takes an integer number and returns an English text sequence starting with the English cardinal representation of that integer, the word 'is' and then the English cardinal representation of the count of characters that made up the first word, followed by a comma.
Continue the sequence by using the previous count word as the first word of the next phrase, append 'is' and the cardinal count of the letters in that word.
Continue until you reach four. Since four has four characters, finish by adding the words 'four is magic' and a period. All integers will eventually wind up at four.
For instance, suppose your are given the integer 3. Convert 3 to Three, add is , then the cardinal character count of three, or five, with a comma to separate if from the next phrase. Continue the sequence five is four, (five has four letters), and finally, four is magic.
Three is five, five is four, four is magic.
For reference, here are outputs for 0 through 9.
Zero is four, four is magic.
One is three, three is five, five is four, four is magic.
Two is three, three is five, five is four, four is magic.
Three is five, five is four, four is magic.
Four is magic.
Five is four, four is magic.
Six is three, three is five, five is four, four is magic.
Seven is five, five is four, four is magic.
Eight is five, five is four, four is magic.
Nine is four, four is magic.
Some task guidelines
You may assume the input will only contain integer numbers.
Cardinal numbers between 20 and 100 may use either hyphens or spaces as word separators but they must use a word separator. (23 is twenty three or twenty-three not twentythree.)
Cardinal number conversions should follow the English short scale. (billion is 1e9, trillion is 1e12, etc.)
Cardinal numbers should not include commas. (20140 is twenty thousand one hundred forty not twenty thousand, one hundred forty.)
When converted to a string, 100 should be one hundred, not a hundred or hundred, 1000 should be one thousand, not a thousand or thousand.
When converted to a string, there should be no and in the cardinal string. 130 should be one hundred thirty not one hundred and thirty.
When counting characters, count all of the characters in the cardinal number including spaces and hyphens. One hundred fifty-one should be 21 not 18.
The output should follow the format "N is K, K is M, M is ... four is magic." (unless the input is 4, in which case the output should simply be "four is magic.")
The output can either be the return value from the function, or be displayed from within the function.
You are encouraged, though not mandated to use proper sentence capitalization.
You may optionally support negative numbers. -7 is negative seven.
Show the output here for a small representative sample of values, at least 5 but no more than 25. You are free to choose which which numbers to use for output demonstration.
You can choose to use a library, (module, external routine, whatever) to do the cardinal conversions as long as the code is easily and freely available to the public.
If you roll your own, make the routine accept at minimum any integer from 0 up to 999999. If you use a pre-made library, support at least up to unsigned 64 bit integers. (or the largest integer supported in your language if it is less.)
Four is magic is a popular code-golf task. This is not code golf. Write legible, idiomatic and well formatted code.
Related tasks
Four is the number of_letters in the ...
Look-and-say sequence
Number names
Self-describing numbers
Summarize and say sequence
Spelling of ordinal numbers
De Bruijn sequences
|
#Wren
|
Wren
|
import "/str" for Str
var small = ["zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten", "eleven",
"twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen"]
var tens = ["", "", "twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"]
var illions = ["", " thousand", " million", " billion"," trillion", " quadrillion", " quintillion"]
var say
say = Fn.new { |n|
var t = ""
if (n < 0) {
t = "negative "
n = -n
}
if (n < 20) {
t = t + small[n]
} else if (n < 100) {
t = t + tens[(n/10).floor]
var s = n % 10
if (s > 0) t = t + "-" + small[s]
} else if (n < 1000) {
t = t + small[(n/100).floor] + " hundred"
var s = n % 100
System.write("") // guards against VM recursion bug
if (s > 0) t = t + " " + say.call(s)
} else {
var sx = ""
var i = 0
while (n > 0) {
var p = n % 1000
n = (n/1000).floor
if (p > 0) {
System.write("") // guards against VM recursion bug
var ix = say.call(p) + illions[i]
if (sx != "") ix = ix + " " + sx
sx = ix
}
i = i + 1
}
t = t + sx
}
return t
}
var fourIsMagic = Fn.new { |n|
var s = Str.capitalize(say.call(n))
var t = s
while (n != 4) {
n = s.count
s = say.call(n)
t = t + " is " + s + ", " + s
}
return t + " is magic."
}
for (n in [0, 4, 6, 11, 13, 75, 100, 337, -164, 9007199254740991]) {
System.print(fourIsMagic.call(n))
}
|
http://rosettacode.org/wiki/Floyd%27s_triangle
|
Floyd's triangle
|
Floyd's triangle lists the natural numbers in a right triangle aligned to the left where
the first row is 1 (unity)
successive rows start towards the left with the next number followed by successive naturals listing one more number than the line above.
The first few lines of a Floyd triangle looks like this:
1
2 3
4 5 6
7 8 9 10
11 12 13 14 15
Task
Write a program to generate and display here the first n lines of a Floyd triangle.
(Use n=5 and n=14 rows).
Ensure that when displayed in a mono-space font, the numbers line up in vertical columns as shown and that only one space separates numbers of the last row.
|
#Bracmat
|
Bracmat
|
( ( floyd
= lowerLeftCorner lastInColumn lastInRow row i W w
. put$(str$("Floyd " !arg ":\n"))
& !arg*(!arg+-1)*1/2+1
: ?lowerLeftCorner
: ?lastInColumn
& 1:?lastInRow:?row:?i
& whl
' ( !row:~>!arg
& @(!lastInColumn:? [?W)
& @(!i:? [?w)
& whl'(!w+1:~>!W:?w&put$" ")
& put$!i
& ( !i:<!lastInRow
& put$" "
& 1+!lastInColumn:?lastInColumn
| put$\n
& (1+!row:?row)+!lastInRow:?lastInRow
& !lowerLeftCorner:?lastInColumn
)
& 1+!i:?i
)
)
& floyd$5
& floyd$14
);
|
http://rosettacode.org/wiki/Floyd%27s_triangle
|
Floyd's triangle
|
Floyd's triangle lists the natural numbers in a right triangle aligned to the left where
the first row is 1 (unity)
successive rows start towards the left with the next number followed by successive naturals listing one more number than the line above.
The first few lines of a Floyd triangle looks like this:
1
2 3
4 5 6
7 8 9 10
11 12 13 14 15
Task
Write a program to generate and display here the first n lines of a Floyd triangle.
(Use n=5 and n=14 rows).
Ensure that when displayed in a mono-space font, the numbers line up in vertical columns as shown and that only one space separates numbers of the last row.
|
#C
|
C
|
#include <stdio.h>
void t(int n)
{
int i, j, c, len;
i = n * (n - 1) / 2;
for (len = c = 1; c < i; c *= 10, len++);
c -= i; // c is the col where width changes
#define SPEED_MATTERS 0
#if SPEED_MATTERS // in case we really, really wanted to print huge triangles often
char tmp[32], s[4096], *p;
sprintf(tmp, "%*d", len, 0);
inline void inc_numstr(void) {
int k = len;
redo: if (!k--) return;
if (tmp[k] == '9') {
tmp[k] = '0';
goto redo;
}
if (++tmp[k] == '!')
tmp[k] = '1';
}
for (p = s, i = 1; i <= n; i++) {
for (j = 1; j <= i; j++) {
inc_numstr();
__builtin_memcpy(p, tmp + 1 - (j >= c), len - (j < c));
p += len - (j < c);
*(p++) = (i - j)? ' ' : '\n';
if (p - s + len >= 4096) {
fwrite(s, 1, p - s, stdout);
p = s;
}
}
}
fwrite(s, 1, p - s, stdout);
#else // NO_IT_DOESN'T
int num;
for (num = i = 1; i <= n; i++)
for (j = 1; j <= i; j++)
printf("%*d%c", len - (j < c), num++, i - j ? ' ':'\n');
#endif
}
int main(void)
{
t(5), t(14);
// maybe not
// t(10000);
return 0;
}
|
http://rosettacode.org/wiki/Floyd-Warshall_algorithm
|
Floyd-Warshall algorithm
|
The Floyd–Warshall algorithm is an algorithm for finding shortest paths in a weighted graph with positive or negative edge weights.
Task
Find the lengths of the shortest paths between all pairs of vertices of the given directed graph. Your code may assume that the input has already been checked for loops, parallel edges and negative cycles.
Print the pair, the distance and (optionally) the path.
Example
pair dist path
1 -> 2 -1 1 -> 3 -> 4 -> 2
1 -> 3 -2 1 -> 3
1 -> 4 0 1 -> 3 -> 4
2 -> 1 4 2 -> 1
2 -> 3 2 2 -> 1 -> 3
2 -> 4 4 2 -> 1 -> 3 -> 4
3 -> 1 5 3 -> 4 -> 2 -> 1
3 -> 2 1 3 -> 4 -> 2
3 -> 4 2 3 -> 4
4 -> 1 3 4 -> 2 -> 1
4 -> 2 -1 4 -> 2
4 -> 3 1 4 -> 2 -> 1 -> 3
See also
Floyd-Warshall Algorithm - step by step guide (youtube)
|
#J
|
J
|
floyd=: verb define
for_j. i.#y do.
y=. y <. j ({"1 +/ {) y
end.
)
|
http://rosettacode.org/wiki/Function_definition
|
Function definition
|
A function is a body of code that returns a value.
The value returned may depend on arguments provided to the function.
Task
Write a definition of a function called "multiply" that takes two arguments and returns their product.
(Argument types should be chosen so as not to distract from showing how functions are created and values returned).
Related task
Function prototype
|
#REBOL
|
REBOL
|
multiply: func [a b][a * b]
|
http://rosettacode.org/wiki/Function_definition
|
Function definition
|
A function is a body of code that returns a value.
The value returned may depend on arguments provided to the function.
Task
Write a definition of a function called "multiply" that takes two arguments and returns their product.
(Argument types should be chosen so as not to distract from showing how functions are created and values returned).
Related task
Function prototype
|
#Relation
|
Relation
|
function multiply(a,b)
set result = a*b
end function
|
http://rosettacode.org/wiki/Forward_difference
|
Forward difference
|
Task
Provide code that produces a list of numbers which is the nth order forward difference, given a non-negative integer (specifying the order) and a list of numbers.
The first-order forward difference of a list of numbers A is a new list B, where Bn = An+1 - An.
List B should have one fewer element as a result.
The second-order forward difference of A will be:
tdefmodule Diff do
def forward(arr,i\\1) do
forward(arr,[],i)
end
def forward([_|[]],diffs,i) do
if i == 1 do
IO.inspect diffs
else
forward(diffs,[],i-1)
end
end
def forward([val1|[val2|vals]],diffs,i) do
forward([val2|vals],diffs++[val2-val1],i)
end
end
The same as the first-order forward difference of B.
That new list will have two fewer elements than A and one less than B.
The goal of this task is to repeat this process up to the desired order.
For a more formal description, see the related Mathworld article.
Algorithmic options
Iterate through all previous forward differences and re-calculate a new array each time.
Use this formula (from Wikipedia):
Δ
n
[
f
]
(
x
)
=
∑
k
=
0
n
(
n
k
)
(
−
1
)
n
−
k
f
(
x
+
k
)
{\displaystyle \Delta ^{n}[f](x)=\sum _{k=0}^{n}{n \choose k}(-1)^{n-k}f(x+k)}
(Pascal's Triangle may be useful for this option.)
|
#M2000_Interpreter
|
M2000 Interpreter
|
Form 80, 40
Module Forward_difference {
Print $(0,6) ' 6 characters column
Dim a(), b()
a()=(90,47,58,29,22,32,55,5,55,73)
Function Diff(a()) {
for i=0 to len(a())-2: a(i)=a(i+1)-a(i):Next i
Dim a(len(a())-1) ' redim one less
=a()
}
Print "Original:","",a()
b()=a() ' copy a() to b()
k=1
While len(b())>1 {
b()=Diff(b()) ' copy returned array to b()
Print "Difference ";k;":",b()
k++
}
}
Forward_difference
|
http://rosettacode.org/wiki/Forward_difference
|
Forward difference
|
Task
Provide code that produces a list of numbers which is the nth order forward difference, given a non-negative integer (specifying the order) and a list of numbers.
The first-order forward difference of a list of numbers A is a new list B, where Bn = An+1 - An.
List B should have one fewer element as a result.
The second-order forward difference of A will be:
tdefmodule Diff do
def forward(arr,i\\1) do
forward(arr,[],i)
end
def forward([_|[]],diffs,i) do
if i == 1 do
IO.inspect diffs
else
forward(diffs,[],i-1)
end
end
def forward([val1|[val2|vals]],diffs,i) do
forward([val2|vals],diffs++[val2-val1],i)
end
end
The same as the first-order forward difference of B.
That new list will have two fewer elements than A and one less than B.
The goal of this task is to repeat this process up to the desired order.
For a more formal description, see the related Mathworld article.
Algorithmic options
Iterate through all previous forward differences and re-calculate a new array each time.
Use this formula (from Wikipedia):
Δ
n
[
f
]
(
x
)
=
∑
k
=
0
n
(
n
k
)
(
−
1
)
n
−
k
f
(
x
+
k
)
{\displaystyle \Delta ^{n}[f](x)=\sum _{k=0}^{n}{n \choose k}(-1)^{n-k}f(x+k)}
(Pascal's Triangle may be useful for this option.)
|
#Mathematica_.2F_Wolfram_Language
|
Mathematica / Wolfram Language
|
i={3,5,12,1,6,19,6,2,4,9};
Differences[i]
|
http://rosettacode.org/wiki/Hello_world/Text
|
Hello world/Text
|
Hello world/Text is part of Short Circuit's Console Program Basics selection.
Task
Display the string Hello world! on a text console.
Related tasks
Hello world/Graphical
Hello world/Line Printer
Hello world/Newbie
Hello world/Newline omission
Hello world/Standard error
Hello world/Web server
|
#Yorick
|
Yorick
|
write, "Hello world!"
|
http://rosettacode.org/wiki/Formatted_numeric_output
|
Formatted numeric output
|
Task
Express a number in decimal as a fixed-length string with leading zeros.
For example, the number 7.125 could be expressed as 00007.125.
|
#Pop11
|
Pop11
|
;;; field of length 12, 3 digits after decimal place
format_print('~12,3,0,`*,`0F', [1299.19]);
;;; prints "00001299.190"
format_print('~12,3,0,`*,`0F', [100000000000000000]);
;;; Since the number does not fit into the field prints "************"
;;; that is stars instead of the number
format_print('~12,3,0,`*,`0F', [-1299.19]);
;;; prints "000-1299.190"
;;; that is _leading zeros_ before sign
format_print('~3,1,12,`0:$', [1299.19]);
;;; prints "00001299.190"
format_print('~3,1,12,`0:$', [-1299.19]);
;;; prints "-0001299.190"
;;; that is sign before leading zeros
format_print('~3,1,12,`0:$', [100000000000000000]);
;;; prints "100000000000000000.000"
;;; that is uses more space if the number does not fit into
;;; fixed width
|
http://rosettacode.org/wiki/Formatted_numeric_output
|
Formatted numeric output
|
Task
Express a number in decimal as a fixed-length string with leading zeros.
For example, the number 7.125 could be expressed as 00007.125.
|
#PowerShell
|
PowerShell
|
'{0:00000.000}' -f 7.125
|
http://rosettacode.org/wiki/Four_bit_adder
|
Four bit adder
|
Task
"Simulate" a four-bit adder.
This design can be realized using four 1-bit full adders.
Each of these 1-bit full adders can be built with two half adders and an or gate. ;
Finally a half adder can be made using an xor gate and an and gate.
The xor gate can be made using two nots, two ands and one or.
Not, or and and, the only allowed "gates" for the task, can be "imitated" by using the bitwise operators of your language.
If there is not a bit type in your language, to be sure that the not does not "invert" all the other bits of the basic type (e.g. a byte) we are not interested in, you can use an extra nand (and then not) with the constant 1 on one input.
Instead of optimizing and reducing the number of gates used for the final 4-bit adder, build it in the most straightforward way, connecting the other "constructive blocks", in turn made of "simpler" and "smaller" ones.
Schematics of the "constructive blocks"
(Xor gate with ANDs, ORs and NOTs)
(A half adder)
(A full adder)
(A 4-bit adder)
Solutions should try to be as descriptive as possible, making it as easy as possible to identify "connections" between higher-order "blocks".
It is not mandatory to replicate the syntax of higher-order blocks in the atomic "gate" blocks, i.e. basic "gate" operations can be performed as usual bitwise operations, or they can be "wrapped" in a block in order to expose the same syntax of higher-order blocks, at implementers' choice.
To test the implementation, show the sum of two four-bit numbers (in binary).
|
#MUMPS
|
MUMPS
|
XOR(Y,Z) ;Uses logicals - i.e., 0 is false, anything else is true (1 is used if setting a value)
QUIT (Y&'Z)!('Y&Z)
HALF(W,X)
QUIT $$XOR(W,X)_"^"_(W&X)
FULL(U,V,CF)
NEW F1,F2
S F1=$$HALF(U,V)
S F2=$$HALF($P(F1,"^",1),CF)
QUIT $P(F2,"^",1)_"^"_($P(F1,"^",2)!($P(F2,"^",2)))
FOUR(Y,Z,C4)
NEW S,I,T
FOR I=4:-1:1 SET T=$$FULL($E(Y,I),$E(Z,I),C4),$E(S,I)=$P(T,"^",1),C4=$P(T,"^",2)
K I,T
QUIT S_"^"_C4
|
http://rosettacode.org/wiki/Fivenum
|
Fivenum
|
Many big data or scientific programs use boxplots to show distributions of data. In addition, sometimes saving large arrays for boxplots can be impractical and use extreme amounts of RAM. It can be useful to save large arrays as arrays with five numbers to save memory.
For example, the R programming language implements Tukey's five-number summary as the fivenum function.
Task
Given an array of numbers, compute the five-number summary.
Note
While these five numbers can be used to draw a boxplot, statistical packages will typically need extra data.
Moreover, while there is a consensus about the "box" of the boxplot, there are variations among statistical packages for the whiskers.
|
#C
|
C
|
#include <stdio.h>
#include <stdlib.h>
double median(double *x, int start, int end_inclusive) {
int size = end_inclusive - start + 1;
if (size <= 0) {
printf("Array slice cannot be empty\n");
exit(1);
}
int m = start + size / 2;
if (size % 2) return x[m];
return (x[m - 1] + x[m]) / 2.0;
}
int compare (const void *a, const void *b) {
double aa = *(double*)a;
double bb = *(double*)b;
if (aa > bb) return 1;
if (aa < bb) return -1;
return 0;
}
int fivenum(double *x, double *result, int x_len) {
int i, m, lower_end;
for (i = 0; i < x_len; i++) {
if (x[i] != x[i]) {
printf("Unable to deal with arrays containing NaN\n\n");
return 1;
}
}
qsort(x, x_len, sizeof(double), compare);
result[0] = x[0];
result[2] = median(x, 0, x_len - 1);
result[4] = x[x_len - 1];
m = x_len / 2;
lower_end = (x_len % 2) ? m : m - 1;
result[1] = median(x, 0, lower_end);
result[3] = median(x, m, x_len - 1);
return 0;
}
int show(double *result, int places) {
int i;
char f[7];
sprintf(f, "%%.%dlf", places);
printf("[");
for (i = 0; i < 5; i++) {
printf(f, result[i]);
if (i < 4) printf(", ");
}
printf("]\n\n");
}
int main() {
double result[5];
double x1[11] = {15.0, 6.0, 42.0, 41.0, 7.0, 36.0, 49.0, 40.0, 39.0, 47.0, 43.0};
if (!fivenum(x1, result, 11)) show(result, 1);
double x2[6] = {36.0, 40.0, 7.0, 39.0, 41.0, 15.0};
if (!fivenum(x2, result, 6)) show(result, 1);
double x3[20] = {
0.14082834, 0.09748790, 1.73131507, 0.87636009, -1.95059594, 0.73438555,
-0.03035726, 1.46675970, -0.74621349, -0.72588772, 0.63905160, 0.61501527,
-0.98983780, -1.00447874, -0.62759469, 0.66206163, 1.04312009, -0.10305385,
0.75775634, 0.32566578
};
if (!fivenum(x3, result, 20)) show(result, 9);
return 0;
}
|
http://rosettacode.org/wiki/First-class_functions
|
First-class functions
|
A language has first-class functions if it can do each of the following without recursively invoking a compiler or interpreter or otherwise metaprogramming:
Create new functions from preexisting functions at run-time
Store functions in collections
Use functions as arguments to other functions
Use functions as return values of other functions
Task
Write a program to create an ordered collection A of functions of a real number. At least one function should be built-in and at least one should be user-defined; try using the sine, cosine, and cubing functions. Fill another collection B with the inverse of each function in A. Implement function composition as in Functional Composition. Finally, demonstrate that the result of applying the composition of each function in A and its inverse in B to a value, is the original value. (Within the limits of computational accuracy).
(A solution need not actually call the collections "A" and "B". These names are only used in the preceding paragraph for clarity.)
Related task
First-class Numbers
|
#ActionScript
|
ActionScript
|
var cube:Function = function(x) {
return Math.pow(x, 3);
};
var cuberoot:Function = function(x) {
return Math.pow(x, 1/3);
};
function compose(f:Function, g:Function):Function {
return function(x:Number) {return f(g(x));};
}
var functions:Array = [Math.cos, Math.tan, cube];
var inverse:Array = [Math.acos, Math.atan, cuberoot];
function test() {
for (var i:uint = 0; i < functions.length; i++) {
// Applying the composition to 0.5
trace(compose(functions[i], inverse[i])(0.5));
}
}
test();
|
http://rosettacode.org/wiki/Forest_fire
|
Forest fire
|
This page uses content from Wikipedia. The original article was at Forest-fire model. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
Task
Implement the Drossel and Schwabl definition of the forest-fire model.
It is basically a 2D cellular automaton where each cell can be in three distinct states (empty, tree and burning) and evolves according to the following rules (as given by Wikipedia)
A burning cell turns into an empty cell
A tree will burn if at least one neighbor is burning
A tree ignites with probability f even if no neighbor is burning
An empty space fills with a tree with probability p
Neighborhood is the Moore neighborhood; boundary conditions are so that on the boundary the cells are always empty ("fixed" boundary condition).
At the beginning, populate the lattice with empty and tree cells according to a specific probability (e.g. a cell has the probability 0.5 to be a tree). Then, let the system evolve.
Task's requirements do not include graphical display or the ability to change parameters (probabilities p and f ) through a graphical or command line interface.
Related tasks
See Conway's Game of Life
See Wireworld.
|
#D
|
D
|
import std.stdio, std.random, std.string, std.algorithm;
enum treeProb = 0.55; // Original tree probability.
enum fProb = 0.01; // Auto combustion probability.
enum cProb = 0.01; // Tree creation probability.
enum Cell : char { empty=' ', tree='T', fire='#' }
alias World = Cell[][];
bool hasBurningNeighbours(in World world, in ulong r, in ulong c)
pure nothrow @safe @nogc {
foreach (immutable rowShift; -1 .. 2)
foreach (immutable colShift; -1 .. 2)
if ((r + rowShift) >= 0 && (r + rowShift) < world.length &&
(c + colShift) >= 0 && (c + colShift) < world[0].length &&
world[r + rowShift][c + colShift] == Cell.fire)
return true;
return false;
}
void nextState(in World world, World nextWorld) /*nothrow*/ @safe /*@nogc*/ {
foreach (r, row; world)
foreach (c, elem; row)
final switch (elem) with (Cell) {
case empty:
nextWorld[r][c]= (uniform01 < cProb) ? tree : empty;
break;
case tree:
if (world.hasBurningNeighbours(r, c))
nextWorld[r][c] = fire;
else
nextWorld[r][c] = (uniform01 < fProb) ? fire : tree;
break;
case fire:
nextWorld[r][c] = empty;
break;
}
}
void main() @safe {
auto world = new World(8, 65);
foreach (row; world)
foreach (ref el; row)
el = (uniform01 < treeProb) ? Cell.tree : Cell.empty;
auto nextWorld = new World(world.length, world[0].length);
foreach (immutable i; 0 .. 4) {
nextState(world, nextWorld);
writefln("%(%(%c%)\n%)\n", nextWorld);
world.swap(nextWorld);
}
}
|
http://rosettacode.org/wiki/First_class_environments
|
First class environments
|
According to Wikipedia, "In computing, a first-class object ... is an entity that can be constructed at run-time, passed as a parameter, returned from a subroutine, or assigned into a variable".
Often this term is used in the context of "first class functions". In an analogous way, a programming language may support "first class environments".
The environment is minimally, the set of variables accessible to a statement being executed. Change the environments and the same statement could produce different results when executed.
Often an environment is captured in a closure, which encapsulates a function together with an environment. That environment, however, is not first-class, as it cannot be created, passed etc. independently from the function's code.
Therefore, a first class environment is a set of variable bindings which can be constructed at run-time, passed as a parameter, returned from a subroutine, or assigned into a variable. It is like a closure without code. A statement must be able to be executed within a stored first class environment and act according to the environment variable values stored within.
Task
Build a dozen environments, and a single piece of code to be run repeatedly in each of these environments.
Each environment contains the bindings for two variables:
a value in the Hailstone sequence, and
a count which is incremented until the value drops to 1.
The initial hailstone values are 1 through 12, and the count in each environment is zero.
When the code runs, it calculates the next hailstone step in the current environment (unless the value is already 1) and counts the steps. Then it prints the current value in a tabular form.
When all hailstone values dropped to 1, processing stops, and the total number of hailstone steps for each environment is printed.
|
#Bracmat
|
Bracmat
|
( (environment=(cnt=0) (seq=))
& :?environments
& 13:?seq
& whl
' ( !seq+-1:>0:?seq
& new$environment:?env
& !seq:?(env..seq)
& !env !environments:?environments
)
& out$(Before !environments)
& whl
' ( !environments:? (=? (seq=>1) ?) ?
& !environments:?envs
& whl
' ( !envs:(=?env) ?envs
& (
' ( $env
(
=
. put$(!(its.seq) \t)
& !(its.seq):1
| 1+!(its.cnt):?(its.cnt)
& 1/2*!(its.seq):~/?(its.seq)
| 3*!(its.seq)+1:?(its.seq)
)
)
.
)
$
)
& out$
)
& out$(After !environments)
)
|
http://rosettacode.org/wiki/First_class_environments
|
First class environments
|
According to Wikipedia, "In computing, a first-class object ... is an entity that can be constructed at run-time, passed as a parameter, returned from a subroutine, or assigned into a variable".
Often this term is used in the context of "first class functions". In an analogous way, a programming language may support "first class environments".
The environment is minimally, the set of variables accessible to a statement being executed. Change the environments and the same statement could produce different results when executed.
Often an environment is captured in a closure, which encapsulates a function together with an environment. That environment, however, is not first-class, as it cannot be created, passed etc. independently from the function's code.
Therefore, a first class environment is a set of variable bindings which can be constructed at run-time, passed as a parameter, returned from a subroutine, or assigned into a variable. It is like a closure without code. A statement must be able to be executed within a stored first class environment and act according to the environment variable values stored within.
Task
Build a dozen environments, and a single piece of code to be run repeatedly in each of these environments.
Each environment contains the bindings for two variables:
a value in the Hailstone sequence, and
a count which is incremented until the value drops to 1.
The initial hailstone values are 1 through 12, and the count in each environment is zero.
When the code runs, it calculates the next hailstone step in the current environment (unless the value is already 1) and counts the steps. Then it prints the current value in a tabular form.
When all hailstone values dropped to 1, processing stops, and the total number of hailstone steps for each environment is printed.
|
#C
|
C
|
#include <stdio.h>
#define JOBS 12
#define jobs(a) for (switch_to(a = 0); a < JOBS || !printf("\n"); switch_to(++a))
typedef struct { int seq, cnt; } env_t;
env_t env[JOBS] = {{0, 0}};
int *seq, *cnt;
void hail()
{
printf("% 4d", *seq);
if (*seq == 1) return;
++*cnt;
*seq = (*seq & 1) ? 3 * *seq + 1 : *seq / 2;
}
void switch_to(int id)
{
seq = &env[id].seq;
cnt = &env[id].cnt;
}
int main()
{
int i;
jobs(i) { env[i].seq = i + 1; }
again: jobs(i) { hail(); }
jobs(i) { if (1 != *seq) goto again; }
printf("COUNTS:\n");
jobs(i) { printf("% 4d", *cnt); }
return 0;
}
|
http://rosettacode.org/wiki/Flatten_a_list
|
Flatten a list
|
Task
Write a function to flatten the nesting in an arbitrary list of values.
Your program should work on the equivalent of this list:
[[1], 2, [[3, 4], 5], [[[]]], [[[6]]], 7, 8, []]
Where the correct result would be the list:
[1, 2, 3, 4, 5, 6, 7, 8]
Related task
Tree traversal
|
#Burlesque
|
Burlesque
|
blsq ) {{1} 2 {{3 4} 5} {{{}}} {{{6}}} 7 8 {}}{\[}{)to{"Block"==}ay}w!
{1 2 3 4 5 6 7 8}
|
http://rosettacode.org/wiki/Flipping_bits_game
|
Flipping bits game
|
The game
Given an N×N square array of zeroes or ones in an initial configuration, and a target configuration of zeroes and ones.
The game is to transform one to the other in as few moves as possible by inverting whole numbered rows or whole lettered
columns at once (as one move).
In an inversion. any 1 becomes 0, and any 0 becomes 1 for that whole row or column.
Task
Create a program to score for the Flipping bits game.
The game should create an original random target configuration and a starting configuration.
Ensure that the starting position is never the target position.
The target position must be guaranteed as reachable from the starting position. (One possible way to do this is to generate the start position by legal flips from a random target position. The flips will always be reversible back to the target from the given start position).
The number of moves taken so far should be shown.
Show an example of a short game here, on this page, for a 3×3 array of bits.
|
#Java
|
Java
|
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
public class FlippingBitsGame extends JPanel {
final int maxLevel = 7;
final int minLevel = 3;
private Random rand = new Random();
private int[][] grid, target;
private Rectangle box;
private int n = maxLevel;
private boolean solved = true;
FlippingBitsGame() {
setPreferredSize(new Dimension(640, 640));
setBackground(Color.white);
setFont(new Font("SansSerif", Font.PLAIN, 18));
box = new Rectangle(120, 90, 400, 400);
startNewGame();
addMouseListener(new MouseAdapter() {
@Override
public void mousePressed(MouseEvent e) {
if (solved) {
startNewGame();
} else {
int x = e.getX();
int y = e.getY();
if (box.contains(x, y))
return;
if (x > box.x && x < box.x + box.width) {
flipCol((x - box.x) / (box.width / n));
} else if (y > box.y && y < box.y + box.height)
flipRow((y - box.y) / (box.height / n));
if (solved(grid, target))
solved = true;
printGrid(solved ? "Solved!" : "The board", grid);
}
repaint();
}
});
}
void startNewGame() {
if (solved) {
n = (n == maxLevel) ? minLevel : n + 1;
grid = new int[n][n];
target = new int[n][n];
do {
shuffle();
for (int i = 0; i < n; i++)
target[i] = Arrays.copyOf(grid[i], n);
shuffle();
} while (solved(grid, target));
solved = false;
printGrid("The target", target);
printGrid("The board", grid);
}
}
void printGrid(String msg, int[][] g) {
System.out.println(msg);
for (int[] row : g)
System.out.println(Arrays.toString(row));
System.out.println();
}
boolean solved(int[][] a, int[][] b) {
for (int i = 0; i < n; i++)
if (!Arrays.equals(a[i], b[i]))
return false;
return true;
}
void shuffle() {
for (int i = 0; i < n * n; i++) {
if (rand.nextBoolean())
flipRow(rand.nextInt(n));
else
flipCol(rand.nextInt(n));
}
}
void flipRow(int r) {
for (int c = 0; c < n; c++) {
grid[r][c] ^= 1;
}
}
void flipCol(int c) {
for (int[] row : grid) {
row[c] ^= 1;
}
}
void drawGrid(Graphics2D g) {
g.setColor(getForeground());
if (solved)
g.drawString("Solved! Click here to play again.", 180, 600);
else
g.drawString("Click next to a row or a column to flip.", 170, 600);
int size = box.width / n;
for (int r = 0; r < n; r++)
for (int c = 0; c < n; c++) {
g.setColor(grid[r][c] == 1 ? Color.blue : Color.orange);
g.fillRect(box.x + c * size, box.y + r * size, size, size);
g.setColor(getBackground());
g.drawRect(box.x + c * size, box.y + r * size, size, size);
g.setColor(target[r][c] == 1 ? Color.blue : Color.orange);
g.fillRect(7 + box.x + c * size, 7 + box.y + r * size, 10, 10);
}
}
@Override
public void paintComponent(Graphics gg) {
super.paintComponent(gg);
Graphics2D g = (Graphics2D) gg;
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
drawGrid(g);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setTitle("Flipping Bits Game");
f.setResizable(false);
f.add(new FlippingBitsGame(), BorderLayout.CENTER);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
});
}
}
|
http://rosettacode.org/wiki/First_power_of_2_that_has_leading_decimal_digits_of_12
|
First power of 2 that has leading decimal digits of 12
|
(This task is taken from a Project Euler problem.)
(All numbers herein are expressed in base ten.)
27 = 128 and 7 is
the first power of 2 whose leading decimal digits are 12.
The next power of 2 whose leading decimal digits
are 12 is 80,
280 = 1208925819614629174706176.
Define p(L,n) to be the nth-smallest
value of j such that the base ten representation
of 2j begins with the digits of L .
So p(12, 1) = 7 and
p(12, 2) = 80
You are also given that:
p(123, 45) = 12710
Task
find:
p(12, 1)
p(12, 2)
p(123, 45)
p(123, 12345)
p(123, 678910)
display the results here, on this page.
|
#F.23
|
F#
|
// First power of 2 that has specified leading decimal digits. Nigel Galloway: March 14th., 2021
let fG n g=let fN l=let l=10.0**(l-floor l) in l>=n && l<g in let f=log10 2.0 in seq{1..0x0FFFFFFF}|>Seq.filter(float>>(*)f>>fN)
printfn "p(23,1)->%d" (int(Seq.item 0 (fG 2.3 2.4)))
printfn "p(99,1)->%d" (int(Seq.item 0 (fG 9.9 10.0)))
printfn "p(12,1)->%d" (int(Seq.item 0 (fG 1.2 1.3)))
printfn "p(12,2)->%d" (int(Seq.item 1 (fG 1.2 1.3)))
printfn "p(123,45)->%d" (int(Seq.item 44 (fG 1.23 1.24)))
printfn "p(123,12345)->%d" (int(Seq.item 12344 (fG 1.23 1.24)))
printfn "p(123,678910)->%d" (int(Seq.item 678909 (fG 1.23 1.24)))
|
http://rosettacode.org/wiki/First-class_functions/Use_numbers_analogously
|
First-class functions/Use numbers analogously
|
In First-class functions, a language is showing how its manipulation of functions is similar to its manipulation of other types.
This tasks aim is to compare and contrast a language's implementation of first class functions, with its normal handling of numbers.
Write a program to create an ordered collection of a mixture of literally typed and expressions producing a real number, together with another ordered collection of their multiplicative inverses. Try and use the following pseudo-code to generate the numbers for the ordered collections:
x = 2.0
xi = 0.5
y = 4.0
yi = 0.25
z = x + y
zi = 1.0 / ( x + y )
Create a function multiplier, that given two numbers as arguments returns a function that when called with one argument, returns the result of multiplying the two arguments to the call to multiplier that created it and the argument in the call:
new_function = multiplier(n1,n2)
# where new_function(m) returns the result of n1 * n2 * m
Applying the multiplier of a number and its inverse from the two ordered collections of numbers in pairs, show that the result in each case is one.
Compare and contrast the resultant program with the corresponding entry in First-class functions. They should be close.
To paraphrase the task description: Do what was done before, but with numbers rather than functions
|
#F.23
|
F#
|
let x = 2.0
let xi = 0.5
let y = 4.0
let yi = 0.25
let z = x + y
let zi = 1.0 / ( x + y )
let multiplier (n1,n2) = fun (m:float) -> n1 * n2 * m
[x; y; z]
|> List.zip [xi; yi; zi]
|> List.map multiplier
|> List.map ((|>) 0.5)
|> printfn "%A"
|
http://rosettacode.org/wiki/First-class_functions/Use_numbers_analogously
|
First-class functions/Use numbers analogously
|
In First-class functions, a language is showing how its manipulation of functions is similar to its manipulation of other types.
This tasks aim is to compare and contrast a language's implementation of first class functions, with its normal handling of numbers.
Write a program to create an ordered collection of a mixture of literally typed and expressions producing a real number, together with another ordered collection of their multiplicative inverses. Try and use the following pseudo-code to generate the numbers for the ordered collections:
x = 2.0
xi = 0.5
y = 4.0
yi = 0.25
z = x + y
zi = 1.0 / ( x + y )
Create a function multiplier, that given two numbers as arguments returns a function that when called with one argument, returns the result of multiplying the two arguments to the call to multiplier that created it and the argument in the call:
new_function = multiplier(n1,n2)
# where new_function(m) returns the result of n1 * n2 * m
Applying the multiplier of a number and its inverse from the two ordered collections of numbers in pairs, show that the result in each case is one.
Compare and contrast the resultant program with the corresponding entry in First-class functions. They should be close.
To paraphrase the task description: Do what was done before, but with numbers rather than functions
|
#Factor
|
Factor
|
USING: arrays kernel literals math prettyprint sequences ;
IN: q
CONSTANT: x 2.0
CONSTANT: xi 0.5
CONSTANT: y 4.0
CONSTANT: yi .25
CONSTANT: z $[ $ x $ y + ]
CONSTANT: zi $[ 1 $ x $ y + / ]
CONSTANT: A ${ x y z }
CONSTANT: B ${ xi yi zi }
: multiplier ( n1 n2 -- q ) [ * * ] 2curry ;
: create-all ( seq1 seq2 -- seq ) [ multiplier ] 2map ;
: example ( -- )
0.5 A B create-all
[ call( x -- y ) ] with map . ;
|
http://rosettacode.org/wiki/Flow-control_structures
|
Flow-control structures
|
Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
Document common flow-control structures.
One common example of a flow-control structure is the goto construct.
Note that Conditional Structures and Loop Structures have their own articles/categories.
Related tasks
Conditional Structures
Loop Structures
|
#jq
|
jq
|
$ jq -n '1, (2 | label $foo | debug | 3 | break $foo | debug), 4'
1
["DEBUG:",2]
4
|
http://rosettacode.org/wiki/Flow-control_structures
|
Flow-control structures
|
Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
Document common flow-control structures.
One common example of a flow-control structure is the goto construct.
Note that Conditional Structures and Loop Structures have their own articles/categories.
Related tasks
Conditional Structures
Loop Structures
|
#Julia
|
Julia
|
function example()
println("Hello ")
@goto world
println("Never printed")
@label world
println("world")
end
|
http://rosettacode.org/wiki/Four_is_magic
|
Four is magic
|
Task
Write a subroutine, function, whatever it may be called in your language, that takes an integer number and returns an English text sequence starting with the English cardinal representation of that integer, the word 'is' and then the English cardinal representation of the count of characters that made up the first word, followed by a comma.
Continue the sequence by using the previous count word as the first word of the next phrase, append 'is' and the cardinal count of the letters in that word.
Continue until you reach four. Since four has four characters, finish by adding the words 'four is magic' and a period. All integers will eventually wind up at four.
For instance, suppose your are given the integer 3. Convert 3 to Three, add is , then the cardinal character count of three, or five, with a comma to separate if from the next phrase. Continue the sequence five is four, (five has four letters), and finally, four is magic.
Three is five, five is four, four is magic.
For reference, here are outputs for 0 through 9.
Zero is four, four is magic.
One is three, three is five, five is four, four is magic.
Two is three, three is five, five is four, four is magic.
Three is five, five is four, four is magic.
Four is magic.
Five is four, four is magic.
Six is three, three is five, five is four, four is magic.
Seven is five, five is four, four is magic.
Eight is five, five is four, four is magic.
Nine is four, four is magic.
Some task guidelines
You may assume the input will only contain integer numbers.
Cardinal numbers between 20 and 100 may use either hyphens or spaces as word separators but they must use a word separator. (23 is twenty three or twenty-three not twentythree.)
Cardinal number conversions should follow the English short scale. (billion is 1e9, trillion is 1e12, etc.)
Cardinal numbers should not include commas. (20140 is twenty thousand one hundred forty not twenty thousand, one hundred forty.)
When converted to a string, 100 should be one hundred, not a hundred or hundred, 1000 should be one thousand, not a thousand or thousand.
When converted to a string, there should be no and in the cardinal string. 130 should be one hundred thirty not one hundred and thirty.
When counting characters, count all of the characters in the cardinal number including spaces and hyphens. One hundred fifty-one should be 21 not 18.
The output should follow the format "N is K, K is M, M is ... four is magic." (unless the input is 4, in which case the output should simply be "four is magic.")
The output can either be the return value from the function, or be displayed from within the function.
You are encouraged, though not mandated to use proper sentence capitalization.
You may optionally support negative numbers. -7 is negative seven.
Show the output here for a small representative sample of values, at least 5 but no more than 25. You are free to choose which which numbers to use for output demonstration.
You can choose to use a library, (module, external routine, whatever) to do the cardinal conversions as long as the code is easily and freely available to the public.
If you roll your own, make the routine accept at minimum any integer from 0 up to 999999. If you use a pre-made library, support at least up to unsigned 64 bit integers. (or the largest integer supported in your language if it is less.)
Four is magic is a popular code-golf task. This is not code golf. Write legible, idiomatic and well formatted code.
Related tasks
Four is the number of_letters in the ...
Look-and-say sequence
Number names
Self-describing numbers
Summarize and say sequence
Spelling of ordinal numbers
De Bruijn sequences
|
#zkl
|
zkl
|
fcn fourIsMagic(int){
if(int==0) return("Zero is four, four is magic.");
string:="";
while(1){ c:=nth(int,False);
string+="%s is ".fmt(c);
if(int = ( if(int==4) 0 else c.len() )){
string+="%s, ".fmt(nth(int,False));
}else{
string+="magic.";
break;
}
}
string[0].toUpper() + string[1,*]
}
|
http://rosettacode.org/wiki/Floyd%27s_triangle
|
Floyd's triangle
|
Floyd's triangle lists the natural numbers in a right triangle aligned to the left where
the first row is 1 (unity)
successive rows start towards the left with the next number followed by successive naturals listing one more number than the line above.
The first few lines of a Floyd triangle looks like this:
1
2 3
4 5 6
7 8 9 10
11 12 13 14 15
Task
Write a program to generate and display here the first n lines of a Floyd triangle.
(Use n=5 and n=14 rows).
Ensure that when displayed in a mono-space font, the numbers line up in vertical columns as shown and that only one space separates numbers of the last row.
|
#C.23
|
C#
|
using System;
using System.Text;
public class FloydsTriangle
{
internal static void Main(string[] args)
{
int count;
if (args.Length >= 1 && int.TryParse(args[0], out count) && count > 0)
{
Console.WriteLine(MakeTriangle(count));
}
else
{
Console.WriteLine(MakeTriangle(5));
Console.WriteLine();
Console.WriteLine(MakeTriangle(14));
}
}
public static string MakeTriangle(int rows)
{
int maxValue = (rows * (rows + 1)) / 2;
int digit = 0;
StringBuilder output = new StringBuilder();
for (int row = 1; row <= rows; row++)
{
for (int column = 0; column < row; column++)
{
int colMaxDigit = (maxValue - rows) + column + 1;
if (column > 0)
{
output.Append(' ');
}
digit++;
output.Append(digit.ToString().PadLeft(colMaxDigit.ToString().Length));
}
output.AppendLine();
}
return output.ToString();
}
}
|
http://rosettacode.org/wiki/Floyd-Warshall_algorithm
|
Floyd-Warshall algorithm
|
The Floyd–Warshall algorithm is an algorithm for finding shortest paths in a weighted graph with positive or negative edge weights.
Task
Find the lengths of the shortest paths between all pairs of vertices of the given directed graph. Your code may assume that the input has already been checked for loops, parallel edges and negative cycles.
Print the pair, the distance and (optionally) the path.
Example
pair dist path
1 -> 2 -1 1 -> 3 -> 4 -> 2
1 -> 3 -2 1 -> 3
1 -> 4 0 1 -> 3 -> 4
2 -> 1 4 2 -> 1
2 -> 3 2 2 -> 1 -> 3
2 -> 4 4 2 -> 1 -> 3 -> 4
3 -> 1 5 3 -> 4 -> 2 -> 1
3 -> 2 1 3 -> 4 -> 2
3 -> 4 2 3 -> 4
4 -> 1 3 4 -> 2 -> 1
4 -> 2 -1 4 -> 2
4 -> 3 1 4 -> 2 -> 1 -> 3
See also
Floyd-Warshall Algorithm - step by step guide (youtube)
|
#Java
|
Java
|
import static java.lang.String.format;
import java.util.Arrays;
public class FloydWarshall {
public static void main(String[] args) {
int[][] weights = {{1, 3, -2}, {2, 1, 4}, {2, 3, 3}, {3, 4, 2}, {4, 2, -1}};
int numVertices = 4;
floydWarshall(weights, numVertices);
}
static void floydWarshall(int[][] weights, int numVertices) {
double[][] dist = new double[numVertices][numVertices];
for (double[] row : dist)
Arrays.fill(row, Double.POSITIVE_INFINITY);
for (int[] w : weights)
dist[w[0] - 1][w[1] - 1] = w[2];
int[][] next = new int[numVertices][numVertices];
for (int i = 0; i < next.length; i++) {
for (int j = 0; j < next.length; j++)
if (i != j)
next[i][j] = j + 1;
}
for (int k = 0; k < numVertices; k++)
for (int i = 0; i < numVertices; i++)
for (int j = 0; j < numVertices; j++)
if (dist[i][k] + dist[k][j] < dist[i][j]) {
dist[i][j] = dist[i][k] + dist[k][j];
next[i][j] = next[i][k];
}
printResult(dist, next);
}
static void printResult(double[][] dist, int[][] next) {
System.out.println("pair dist path");
for (int i = 0; i < next.length; i++) {
for (int j = 0; j < next.length; j++) {
if (i != j) {
int u = i + 1;
int v = j + 1;
String path = format("%d -> %d %2d %s", u, v,
(int) dist[i][j], u);
do {
u = next[u - 1][v - 1];
path += " -> " + u;
} while (u != v);
System.out.println(path);
}
}
}
}
}
|
http://rosettacode.org/wiki/Function_definition
|
Function definition
|
A function is a body of code that returns a value.
The value returned may depend on arguments provided to the function.
Task
Write a definition of a function called "multiply" that takes two arguments and returns their product.
(Argument types should be chosen so as not to distract from showing how functions are created and values returned).
Related task
Function prototype
|
#Retro
|
Retro
|
: multiply ( nn-n ) * ;
|
http://rosettacode.org/wiki/Function_definition
|
Function definition
|
A function is a body of code that returns a value.
The value returned may depend on arguments provided to the function.
Task
Write a definition of a function called "multiply" that takes two arguments and returns their product.
(Argument types should be chosen so as not to distract from showing how functions are created and values returned).
Related task
Function prototype
|
#REXX
|
REXX
|
multiply: return arg(1) * arg(2) /*return the product of the two arguments.*/
|
http://rosettacode.org/wiki/Forward_difference
|
Forward difference
|
Task
Provide code that produces a list of numbers which is the nth order forward difference, given a non-negative integer (specifying the order) and a list of numbers.
The first-order forward difference of a list of numbers A is a new list B, where Bn = An+1 - An.
List B should have one fewer element as a result.
The second-order forward difference of A will be:
tdefmodule Diff do
def forward(arr,i\\1) do
forward(arr,[],i)
end
def forward([_|[]],diffs,i) do
if i == 1 do
IO.inspect diffs
else
forward(diffs,[],i-1)
end
end
def forward([val1|[val2|vals]],diffs,i) do
forward([val2|vals],diffs++[val2-val1],i)
end
end
The same as the first-order forward difference of B.
That new list will have two fewer elements than A and one less than B.
The goal of this task is to repeat this process up to the desired order.
For a more formal description, see the related Mathworld article.
Algorithmic options
Iterate through all previous forward differences and re-calculate a new array each time.
Use this formula (from Wikipedia):
Δ
n
[
f
]
(
x
)
=
∑
k
=
0
n
(
n
k
)
(
−
1
)
n
−
k
f
(
x
+
k
)
{\displaystyle \Delta ^{n}[f](x)=\sum _{k=0}^{n}{n \choose k}(-1)^{n-k}f(x+k)}
(Pascal's Triangle may be useful for this option.)
|
#MATLAB_.2F_Octave
|
MATLAB / Octave
|
Y = diff(X,n);
|
http://rosettacode.org/wiki/Forward_difference
|
Forward difference
|
Task
Provide code that produces a list of numbers which is the nth order forward difference, given a non-negative integer (specifying the order) and a list of numbers.
The first-order forward difference of a list of numbers A is a new list B, where Bn = An+1 - An.
List B should have one fewer element as a result.
The second-order forward difference of A will be:
tdefmodule Diff do
def forward(arr,i\\1) do
forward(arr,[],i)
end
def forward([_|[]],diffs,i) do
if i == 1 do
IO.inspect diffs
else
forward(diffs,[],i-1)
end
end
def forward([val1|[val2|vals]],diffs,i) do
forward([val2|vals],diffs++[val2-val1],i)
end
end
The same as the first-order forward difference of B.
That new list will have two fewer elements than A and one less than B.
The goal of this task is to repeat this process up to the desired order.
For a more formal description, see the related Mathworld article.
Algorithmic options
Iterate through all previous forward differences and re-calculate a new array each time.
Use this formula (from Wikipedia):
Δ
n
[
f
]
(
x
)
=
∑
k
=
0
n
(
n
k
)
(
−
1
)
n
−
k
f
(
x
+
k
)
{\displaystyle \Delta ^{n}[f](x)=\sum _{k=0}^{n}{n \choose k}(-1)^{n-k}f(x+k)}
(Pascal's Triangle may be useful for this option.)
|
#Maxima
|
Maxima
|
ldiff(u, n) := block([m: length(u)], for j thru n do u: makelist(u[i + 1] - u[i], i, 1, m - j), u);
|
http://rosettacode.org/wiki/Hello_world/Text
|
Hello world/Text
|
Hello world/Text is part of Short Circuit's Console Program Basics selection.
Task
Display the string Hello world! on a text console.
Related tasks
Hello world/Graphical
Hello world/Line Printer
Hello world/Newbie
Hello world/Newline omission
Hello world/Standard error
Hello world/Web server
|
#Z80_Assembly
|
Z80 Assembly
|
org $4000
txt_output: equ $bb5a
push hl
ld hl,world
print: ld a,(hl)
cp 0
jr z,end
call txt_output
inc hl
jr print
end: pop hl
ret
world: defm "Hello world!\r\n\0"
|
http://rosettacode.org/wiki/Formatted_numeric_output
|
Formatted numeric output
|
Task
Express a number in decimal as a fixed-length string with leading zeros.
For example, the number 7.125 could be expressed as 00007.125.
|
#PureBasic
|
PureBasic
|
RSet(StrF(7.125,3),8,"0") ; Will be 0007.125
|
http://rosettacode.org/wiki/Formatted_numeric_output
|
Formatted numeric output
|
Task
Express a number in decimal as a fixed-length string with leading zeros.
For example, the number 7.125 could be expressed as 00007.125.
|
#Python
|
Python
|
from math import pi, exp
r = exp(pi)-pi
print r
print "e=%e f=%f g=%g G=%G s=%s r=%r!"%(r,r,r,r,r,r)
print "e=%9.4e f=%9.4f g=%9.4g!"%(-r,-r,-r)
print "e=%9.4e f=%9.4f g=%9.4g!"%(r,r,r)
print "e=%-9.4e f=%-9.4f g=%-9.4g!"%(r,r,r)
print "e=%09.4e f=%09.4f g=%09.4g!"%(-r,-r,-r)
print "e=%09.4e f=%09.4f g=%09.4g!"%(r,r,r)
print "e=%-09.4e f=%-09.4f g=%-09.4g!"%(r,r,r)
|
http://rosettacode.org/wiki/Four_bit_adder
|
Four bit adder
|
Task
"Simulate" a four-bit adder.
This design can be realized using four 1-bit full adders.
Each of these 1-bit full adders can be built with two half adders and an or gate. ;
Finally a half adder can be made using an xor gate and an and gate.
The xor gate can be made using two nots, two ands and one or.
Not, or and and, the only allowed "gates" for the task, can be "imitated" by using the bitwise operators of your language.
If there is not a bit type in your language, to be sure that the not does not "invert" all the other bits of the basic type (e.g. a byte) we are not interested in, you can use an extra nand (and then not) with the constant 1 on one input.
Instead of optimizing and reducing the number of gates used for the final 4-bit adder, build it in the most straightforward way, connecting the other "constructive blocks", in turn made of "simpler" and "smaller" ones.
Schematics of the "constructive blocks"
(Xor gate with ANDs, ORs and NOTs)
(A half adder)
(A full adder)
(A 4-bit adder)
Solutions should try to be as descriptive as possible, making it as easy as possible to identify "connections" between higher-order "blocks".
It is not mandatory to replicate the syntax of higher-order blocks in the atomic "gate" blocks, i.e. basic "gate" operations can be performed as usual bitwise operations, or they can be "wrapped" in a block in order to expose the same syntax of higher-order blocks, at implementers' choice.
To test the implementation, show the sum of two four-bit numbers (in binary).
|
#MyHDL
|
MyHDL
|
"""
To run:
python3 Four_bit_adder_011.py
"""
from myhdl import *
# define set of primitives
@block
def NOTgate( a, q ): # define component name & interface
""" q <- not(a) """
@always_comb # define asynchronous logic
def NOTgateLogic():
q.next = not a
return NOTgateLogic # return defined logic function, named 'NOTgate'
@block
def ANDgate( a, b, q ):
""" q <- a and b """
@always_comb
def ANDgateLogic():
q.next = a and b
return ANDgateLogic
@block
def ORgate( a, b, q ):
""" q <- a or b """
@always_comb
def ORgateLogic():
q.next = a or b
return ORgateLogic
# build components using defined primitive set
@block
def XORgate( a, b, q ):
""" q <- a xor b """
# define internal signals
nota, notb, annotb, bnnota = [Signal(bool(0)) for i in range(4)]
# name sub-components, and their interconnect
inv0 = NOTgate( a, nota )
inv1 = NOTgate( b, notb )
and2a = ANDgate( a, notb, annotb )
and2b = ANDgate( b, nota, bnnota )
or2a = ORgate( annotb, bnnota, q )
return inv0, inv1, and2a, and2b, or2a
@block
def HalfAdder( in_a, in_b, summ, carry ):
""" carry,sum is the sum of in_a, in_b """
and2a = ANDgate(in_a, in_b, carry)
xor2a = XORgate(in_a, in_b, summ)
return and2a, xor2a
@block
def FullAdder( fa_c0, fa_a, fa_b, fa_s, fa_c1 ):
""" fa_c1,fa_s is the sum of fa_c0, fa_a, fa_b """
ha1_s, ha1_c1, ha2_c1 = [Signal(bool(0)) for i in range(3)]
HalfAdder01 = HalfAdder( fa_c0, fa_a, ha1_s, ha1_c1 )
HalfAdder02 = HalfAdder( ha1_s, fa_b, fa_s, ha2_c1 )
or2a = ORgate(ha1_c1, ha2_c1, fa_c1)
return HalfAdder01, HalfAdder02, or2a
@block
def Adder4b( ina, inb, cOut, sum4):
''' assemble 4 full adders '''
cl = [Signal(bool()) for i in range(0,4)] # carry signal list
sl = [Signal(bool()) for i in range(4)] # sum signal list
HalfAdder0 = HalfAdder( ina(0), inb(0), sl[0], cl[1] )
FullAdder1 = FullAdder( cl[1], ina(1), inb(1), sl[1], cl[2] )
FullAdder2 = FullAdder( cl[2], ina(2), inb(2), sl[2], cl[3] )
FullAdder3 = FullAdder( cl[3], ina(3), inb(3), sl[3], cOut )
sc = ConcatSignal(*reversed(sl)) # create internal bus for output list
@always_comb
def list2intbv():
sum4.next = sc # assign internal bus to actual output
return HalfAdder0, FullAdder1, FullAdder2, FullAdder3, list2intbv
""" define signals and code for testing
----------------------------------- """
t_co, t_s, t_a, t_b, dbug = [Signal(bool(0)) for i in range(5)]
ina4, inb4, sum4 = [Signal(intbv(0)[4:]) for i in range(3)]
from random import randrange
@block
def Test_Adder4b():
''' Test Bench for Adder4b '''
dut = Adder4b( ina4, inb4, t_co, sum4 )
@instance
def check():
print( "\n b a | c1 s \n -------------------" )
for i in range(15):
ina4.next, inb4.next = randrange(2**4), randrange(2**4)
yield delay(5)
print( " %2d %2d | %2d %2d " \
% (ina4,inb4, t_co,sum4) )
assert t_co * 16 + sum4 == ina4 + inb4 # test result
print()
return dut, check
""" instantiate components and run test
----------------------------------- """
def main():
simInst = Test_Adder4b()
simInst.name = "mySimInst"
simInst.config_sim(trace=True) # waveform trace turned on
simInst.run_sim(duration=None)
inst = Adder4b( ina4, inb4, t_co, sum4 ) #Multibit_Adder( a, b, s)
inst.convert(hdl='VHDL') # export VHDL
inst.convert(hdl='Verilog') # export Verilog
if __name__ == '__main__':
main()
|
http://rosettacode.org/wiki/Fivenum
|
Fivenum
|
Many big data or scientific programs use boxplots to show distributions of data. In addition, sometimes saving large arrays for boxplots can be impractical and use extreme amounts of RAM. It can be useful to save large arrays as arrays with five numbers to save memory.
For example, the R programming language implements Tukey's five-number summary as the fivenum function.
Task
Given an array of numbers, compute the five-number summary.
Note
While these five numbers can be used to draw a boxplot, statistical packages will typically need extra data.
Moreover, while there is a consensus about the "box" of the boxplot, there are variations among statistical packages for the whiskers.
|
#C.23
|
C#
|
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Fivenum {
public static class Helper {
public static string AsString<T>(this ICollection<T> c, string format = "{0}") {
StringBuilder sb = new StringBuilder("[");
int count = 0;
foreach (var t in c) {
if (count++ > 0) {
sb.Append(", ");
}
sb.AppendFormat(format, t);
}
return sb.Append("]").ToString();
}
}
class Program {
static double Median(double[] x, int start, int endInclusive) {
int size = endInclusive - start + 1;
if (size <= 0) throw new ArgumentException("Array slice cannot be empty");
int m = start + size / 2;
return (size % 2 == 1) ? x[m] : (x[m - 1] + x[m]) / 2.0;
}
static double[] Fivenum(double[] x) {
foreach (var d in x) {
if (Double.IsNaN(d)) {
throw new ArgumentException("Unable to deal with arrays containing NaN");
}
}
double[] result = new double[5];
Array.Sort(x);
result[0] = x.First();
result[2] = Median(x, 0, x.Length - 1);
result[4] = x.Last();
int m = x.Length / 2;
int lowerEnd = (x.Length % 2 == 1) ? m : m - 1;
result[1] = Median(x, 0, lowerEnd);
result[3] = Median(x, m, x.Length - 1);
return result;
}
static void Main(string[] args) {
double[][] x1 = new double[][]{
new double[]{ 15.0, 6.0, 42.0, 41.0, 7.0, 36.0, 49.0, 40.0, 39.0, 47.0, 43.0},
new double[]{ 36.0, 40.0, 7.0, 39.0, 41.0, 15.0},
new double[]{
0.14082834, 0.09748790, 1.73131507, 0.87636009, -1.95059594, 0.73438555,
-0.03035726, 1.46675970, -0.74621349, -0.72588772, 0.63905160, 0.61501527,
-0.98983780, -1.00447874, -0.62759469, 0.66206163, 1.04312009, -0.10305385,
0.75775634, 0.32566578
},
};
foreach(var x in x1) {
var result = Fivenum(x);
Console.WriteLine(result.AsString("{0:F8}"));
}
}
}
}
|
http://rosettacode.org/wiki/First-class_functions
|
First-class functions
|
A language has first-class functions if it can do each of the following without recursively invoking a compiler or interpreter or otherwise metaprogramming:
Create new functions from preexisting functions at run-time
Store functions in collections
Use functions as arguments to other functions
Use functions as return values of other functions
Task
Write a program to create an ordered collection A of functions of a real number. At least one function should be built-in and at least one should be user-defined; try using the sine, cosine, and cubing functions. Fill another collection B with the inverse of each function in A. Implement function composition as in Functional Composition. Finally, demonstrate that the result of applying the composition of each function in A and its inverse in B to a value, is the original value. (Within the limits of computational accuracy).
(A solution need not actually call the collections "A" and "B". These names are only used in the preceding paragraph for clarity.)
Related task
First-class Numbers
|
#Ada
|
Ada
|
with Ada.Float_Text_IO,
Ada.Integer_Text_IO,
Ada.Text_IO,
Ada.Numerics.Elementary_Functions;
procedure First_Class_Functions is
use Ada.Float_Text_IO,
Ada.Integer_Text_IO,
Ada.Text_IO,
Ada.Numerics.Elementary_Functions;
function Sqr (X : Float) return Float is
begin
return X ** 2;
end Sqr;
type A_Function is access function (X : Float) return Float;
generic
F, G : A_Function;
function Compose (X : Float) return Float;
function Compose (X : Float) return Float is
begin
return F (G (X));
end Compose;
Functions : array (Positive range <>) of A_Function := (Sin'Access,
Cos'Access,
Sqr'Access);
Inverses : array (Positive range <>) of A_Function := (Arcsin'Access,
Arccos'Access,
Sqrt'Access);
begin
for I in Functions'Range loop
declare
function Identity is new Compose (Functions (I), Inverses (I));
Test_Value : Float := 0.5;
Result : Float;
begin
Result := Identity (Test_Value);
if Result = Test_Value then
Put ("Example ");
Put (I, Width => 0);
Put_Line (" is perfect for the given test value.");
else
Put ("Example ");
Put (I, Width => 0);
Put (" is off by");
Put (abs (Result - Test_Value));
Put_Line (" for the given test value.");
end if;
end;
end loop;
end First_Class_Functions;
|
http://rosettacode.org/wiki/Forest_fire
|
Forest fire
|
This page uses content from Wikipedia. The original article was at Forest-fire model. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
Task
Implement the Drossel and Schwabl definition of the forest-fire model.
It is basically a 2D cellular automaton where each cell can be in three distinct states (empty, tree and burning) and evolves according to the following rules (as given by Wikipedia)
A burning cell turns into an empty cell
A tree will burn if at least one neighbor is burning
A tree ignites with probability f even if no neighbor is burning
An empty space fills with a tree with probability p
Neighborhood is the Moore neighborhood; boundary conditions are so that on the boundary the cells are always empty ("fixed" boundary condition).
At the beginning, populate the lattice with empty and tree cells according to a specific probability (e.g. a cell has the probability 0.5 to be a tree). Then, let the system evolve.
Task's requirements do not include graphical display or the ability to change parameters (probabilities p and f ) through a graphical or command line interface.
Related tasks
See Conway's Game of Life
See Wireworld.
|
#D.C3.A9j.C3.A0_Vu
|
Déjà Vu
|
#chance of empty->tree
set :p 0.004
#chance of spontaneous tree combustion
set :f 0.001
#chance of tree in initial state
set :s 0.5
#height of world
set :H 10
#width of world
set :W 20
has-burning-neigbour state pos:
for i range -- swap ++ dup &< pos:
for j range -- swap ++ dup &> pos:
& i j
try:
state!
catch value-error:
:empty
if = :burning:
return true
false
evolve state pos:
state! pos
if = :tree dup:
if has-burning-neigbour state pos:
:burning drop
elseif chance f:
:burning drop
elseif = :burning:
:empty
else:
if chance p:
:tree
else:
:empty
step state:
local :next {}
for k in keys state:
set-to next k evolve state k
next
local :(c) { :tree "T" :burning "B" :empty "." }
print-state state:
for j range 0 H:
for i range 0 W:
!print\ (c)! state! & i j
!print ""
init-state:
local :first {}
for j range 0 H:
for i range 0 W:
if chance s:
:tree
else:
:empty
set-to first & i j
first
run:
init-state
while true:
print-state dup
!print ""
step
run-slowly:
init-state
while true:
print-state dup
drop !prompt "Continue."
step
run
|
http://rosettacode.org/wiki/First_class_environments
|
First class environments
|
According to Wikipedia, "In computing, a first-class object ... is an entity that can be constructed at run-time, passed as a parameter, returned from a subroutine, or assigned into a variable".
Often this term is used in the context of "first class functions". In an analogous way, a programming language may support "first class environments".
The environment is minimally, the set of variables accessible to a statement being executed. Change the environments and the same statement could produce different results when executed.
Often an environment is captured in a closure, which encapsulates a function together with an environment. That environment, however, is not first-class, as it cannot be created, passed etc. independently from the function's code.
Therefore, a first class environment is a set of variable bindings which can be constructed at run-time, passed as a parameter, returned from a subroutine, or assigned into a variable. It is like a closure without code. A statement must be able to be executed within a stored first class environment and act according to the environment variable values stored within.
Task
Build a dozen environments, and a single piece of code to be run repeatedly in each of these environments.
Each environment contains the bindings for two variables:
a value in the Hailstone sequence, and
a count which is incremented until the value drops to 1.
The initial hailstone values are 1 through 12, and the count in each environment is zero.
When the code runs, it calculates the next hailstone step in the current environment (unless the value is already 1) and counts the steps. Then it prints the current value in a tabular form.
When all hailstone values dropped to 1, processing stops, and the total number of hailstone steps for each environment is printed.
|
#Clojure
|
Clojure
|
(def hailstone-src
"(defn hailstone-step [env]
(let [{:keys[n cnt]} env]
(cond
(= n 1) {:n 1 :cnt cnt}
(even? n) {:n (/ n 2) :cnt (inc cnt)}
:else {:n (inc (* n 3)) :cnt (inc cnt)})))")
(defn create-hailstone-table [f-src]
(let [done? (fn [e] (= (:n e) 1))
print-step (fn [envs] (println (map #(format "%4d" (:n %)) envs)))
print-counts (fn [envs] (println "Counts:\n"
(map #(format "%4d" (:cnt %)) envs)))]
(loop [f (eval (read-string f-src))
envs (for [n (range 12)]
{:n (inc n) :cnt 0})]
(if (every? done? envs)
(print-counts envs)
(do
(print-step envs)
(recur f (map f envs)))))))
|
http://rosettacode.org/wiki/First_class_environments
|
First class environments
|
According to Wikipedia, "In computing, a first-class object ... is an entity that can be constructed at run-time, passed as a parameter, returned from a subroutine, or assigned into a variable".
Often this term is used in the context of "first class functions". In an analogous way, a programming language may support "first class environments".
The environment is minimally, the set of variables accessible to a statement being executed. Change the environments and the same statement could produce different results when executed.
Often an environment is captured in a closure, which encapsulates a function together with an environment. That environment, however, is not first-class, as it cannot be created, passed etc. independently from the function's code.
Therefore, a first class environment is a set of variable bindings which can be constructed at run-time, passed as a parameter, returned from a subroutine, or assigned into a variable. It is like a closure without code. A statement must be able to be executed within a stored first class environment and act according to the environment variable values stored within.
Task
Build a dozen environments, and a single piece of code to be run repeatedly in each of these environments.
Each environment contains the bindings for two variables:
a value in the Hailstone sequence, and
a count which is incremented until the value drops to 1.
The initial hailstone values are 1 through 12, and the count in each environment is zero.
When the code runs, it calculates the next hailstone step in the current environment (unless the value is already 1) and counts the steps. Then it prints the current value in a tabular form.
When all hailstone values dropped to 1, processing stops, and the total number of hailstone steps for each environment is printed.
|
#D
|
D
|
import std.stdio, std.algorithm, std.range, std.array;
struct Prop {
int[string] data;
ref opDispatch(string s)() pure nothrow {
return data[s];
}
}
immutable code = `
writef("% 4d", e.seq);
if (e.seq != 1) {
e.cnt++;
e.seq = (e.seq & 1) ? 3 * e.seq + 1 : e.seq / 2;
}`;
void main() {
auto envs = 12.iota.map!(i => Prop(["cnt": 0, "seq": i+1])).array;
while (envs.any!(env => env.seq > 1)) {
foreach (e; envs) {
mixin(code);
}
writeln;
}
writefln("Counts:\n%(% 4d%)", envs.map!(env => env.cnt));
}
|
http://rosettacode.org/wiki/Flatten_a_list
|
Flatten a list
|
Task
Write a function to flatten the nesting in an arbitrary list of values.
Your program should work on the equivalent of this list:
[[1], 2, [[3, 4], 5], [[[]]], [[[6]]], 7, 8, []]
Where the correct result would be the list:
[1, 2, 3, 4, 5, 6, 7, 8]
Related task
Tree traversal
|
#C
|
C
|
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct list_t list_t, *list;
struct list_t{
int is_list, ival; /* ival is either the integer value or list length */
list *lst;
};
list new_list()
{
list x = malloc(sizeof(list_t));
x->ival = 0;
x->is_list = 1;
x->lst = 0;
return x;
}
void append(list parent, list child)
{
parent->lst = realloc(parent->lst, sizeof(list) * (parent->ival + 1));
parent->lst[parent->ival++] = child;
}
list from_string(char *s, char **e, list parent)
{
list ret = 0;
if (!parent) parent = new_list();
while (*s != '\0') {
if (*s == ']') {
if (e) *e = s + 1;
return parent;
}
if (*s == '[') {
ret = new_list();
ret->is_list = 1;
ret->ival = 0;
append(parent, ret);
from_string(s + 1, &s, ret);
continue;
}
if (*s >= '0' && *s <= '9') {
ret = new_list();
ret->is_list = 0;
ret->ival = strtol(s, &s, 10);
append(parent, ret);
continue;
}
s++;
}
if (e) *e = s;
return parent;
}
void show_list(list l)
{
int i;
if (!l) return;
if (!l->is_list) {
printf("%d", l->ival);
return;
}
printf("[");
for (i = 0; i < l->ival; i++) {
show_list(l->lst[i]);
if (i < l->ival - 1) printf(", ");
}
printf("]");
}
list flatten(list from, list to)
{
int i;
list t;
if (!to) to = new_list();
if (!from->is_list) {
t = new_list();
*t = *from;
append(to, t);
} else
for (i = 0; i < from->ival; i++)
flatten(from->lst[i], to);
return to;
}
void delete_list(list l)
{
int i;
if (!l) return;
if (l->is_list && l->ival) {
for (i = 0; i < l->ival; i++)
delete_list(l->lst[i]);
free(l->lst);
}
free(l);
}
int main()
{
list l = from_string("[1], 2, [[3,4], 5], [[[]]], [[[6]]], 7, 8, []", 0, 0);
printf("Nested: ");
show_list(l);
printf("\n");
list flat = flatten(l, 0);
printf("Flattened: ");
show_list(flat);
/* delete_list(l); delete_list(flat); */
return 0;
}
|
http://rosettacode.org/wiki/Flipping_bits_game
|
Flipping bits game
|
The game
Given an N×N square array of zeroes or ones in an initial configuration, and a target configuration of zeroes and ones.
The game is to transform one to the other in as few moves as possible by inverting whole numbered rows or whole lettered
columns at once (as one move).
In an inversion. any 1 becomes 0, and any 0 becomes 1 for that whole row or column.
Task
Create a program to score for the Flipping bits game.
The game should create an original random target configuration and a starting configuration.
Ensure that the starting position is never the target position.
The target position must be guaranteed as reachable from the starting position. (One possible way to do this is to generate the start position by legal flips from a random target position. The flips will always be reversible back to the target from the given start position).
The number of moves taken so far should be shown.
Show an example of a short game here, on this page, for a 3×3 array of bits.
|
#JavaScript
|
JavaScript
|
function numOfRows(board) { return board.length; }
function numOfCols(board) { return board[0].length; }
function boardToString(board) {
// First the top-header
var header = ' ';
for (var c = 0; c < numOfCols(board); c++)
header += c + ' ';
// Then the side-header + board
var sideboard = [];
for (var r = 0; r < numOfRows(board); r++) {
sideboard.push(r + ' [' + board[r].join(' ') + ']');
}
return header + '\n' + sideboard.join('\n');
}
function flipRow(board, row) {
for (var c = 0; c < numOfCols(board); c++) {
board[row][c] = 1 - board[row][c];
}
}
function flipCol(board, col) {
for (var r = 0; r < numOfRows(board); r++) {
board[r][col] = 1 - board[r][col];
}
}
function playFlippingBitsGame(rows, cols) {
rows = rows | 3;
cols = cols | 3;
var targetBoard = [];
var manipulatedBoard = [];
// Randomly generate two identical boards.
for (var r = 0; r < rows; r++) {
targetBoard.push([]);
manipulatedBoard.push([]);
for (var c = 0; c < cols; c++) {
targetBoard[r].push(Math.floor(Math.random() * 2));
manipulatedBoard[r].push(targetBoard[r][c]);
}
}
// Naive-scramble one of the boards.
while (boardToString(targetBoard) == boardToString(manipulatedBoard)) {
var scrambles = rows * cols;
while (scrambles-- > 0) {
if (0 == Math.floor(Math.random() * 2)) {
flipRow(manipulatedBoard, Math.floor(Math.random() * rows));
}
else {
flipCol(manipulatedBoard, Math.floor(Math.random() * cols));
}
}
}
// Get the user to solve.
alert(
'Try to match both boards.\n' +
'Enter `r<num>` or `c<num>` to manipulate a row or col or enter `q` to quit.'
);
var input = '', letter, num, moves = 0;
while (boardToString(targetBoard) != boardToString(manipulatedBoard) && input != 'q') {
input = prompt(
'Target:\n' + boardToString(targetBoard) +
'\n\n\n' +
'Board:\n' + boardToString(manipulatedBoard)
);
try {
letter = input.charAt(0);
num = parseInt(input.slice(1));
if (letter == 'q')
break;
if (isNaN(num)
|| (letter != 'r' && letter != 'c')
|| (letter == 'r' && num >= rows)
|| (letter == 'c' && num >= cols)
) {
throw new Error('');
}
if (letter == 'r') {
flipRow(manipulatedBoard, num);
}
else {
flipCol(manipulatedBoard, num);
}
moves++;
}
catch(e) {
alert('Uh-oh, there seems to have been an input error');
}
}
if (input == 'q') {
alert('~~ Thanks for playing ~~');
}
else {
alert('Completed in ' + moves + ' moves.');
}
}
|
http://rosettacode.org/wiki/First_power_of_2_that_has_leading_decimal_digits_of_12
|
First power of 2 that has leading decimal digits of 12
|
(This task is taken from a Project Euler problem.)
(All numbers herein are expressed in base ten.)
27 = 128 and 7 is
the first power of 2 whose leading decimal digits are 12.
The next power of 2 whose leading decimal digits
are 12 is 80,
280 = 1208925819614629174706176.
Define p(L,n) to be the nth-smallest
value of j such that the base ten representation
of 2j begins with the digits of L .
So p(12, 1) = 7 and
p(12, 2) = 80
You are also given that:
p(123, 45) = 12710
Task
find:
p(12, 1)
p(12, 2)
p(123, 45)
p(123, 12345)
p(123, 678910)
display the results here, on this page.
|
#Factor
|
Factor
|
USING: formatting fry generalizations kernel literals math
math.functions math.parser sequences tools.time ;
CONSTANT: ld10 $[ 2 log 10 log / ]
: p ( L n -- m )
swap [ 0 0 ]
[ '[ over _ >= ] ]
[ [ log10 >integer 10^ ] keep ] tri*
'[
1 + dup ld10 * dup >integer - 10 log * e^ _ * truncate
_ number= [ [ 1 + ] dip ] when
] until nip ;
[
12 1
12 2
123 45
123 12345
123 678910
[ 2dup p "%d %d p = %d\n" printf ] 2 5 mnapply
] time
|
http://rosettacode.org/wiki/First_power_of_2_that_has_leading_decimal_digits_of_12
|
First power of 2 that has leading decimal digits of 12
|
(This task is taken from a Project Euler problem.)
(All numbers herein are expressed in base ten.)
27 = 128 and 7 is
the first power of 2 whose leading decimal digits are 12.
The next power of 2 whose leading decimal digits
are 12 is 80,
280 = 1208925819614629174706176.
Define p(L,n) to be the nth-smallest
value of j such that the base ten representation
of 2j begins with the digits of L .
So p(12, 1) = 7 and
p(12, 2) = 80
You are also given that:
p(123, 45) = 12710
Task
find:
p(12, 1)
p(12, 2)
p(123, 45)
p(123, 12345)
p(123, 678910)
display the results here, on this page.
|
#FreeBASIC
|
FreeBASIC
|
#define FAC 0.30102999566398119521373889472449302677
function p( L as uinteger, n as uinteger ) as uinteger
dim as uinteger count, j = 0
dim as double x, y
dim as string digits, LS = str(L)
while count < n
j+=1
x = FAC * j
if x < len(LS) then continue while
y = 10^(x-int(x))
y *= 10^len(LS)
digits = str(y)
if left(digits,len(LS)) = LS then count += 1
wend
return j
end function
print p(12, 1)
print p(12, 2)
print p(123, 45)
print p(123, 12345)
print p(123, 678910)
|
http://rosettacode.org/wiki/First-class_functions/Use_numbers_analogously
|
First-class functions/Use numbers analogously
|
In First-class functions, a language is showing how its manipulation of functions is similar to its manipulation of other types.
This tasks aim is to compare and contrast a language's implementation of first class functions, with its normal handling of numbers.
Write a program to create an ordered collection of a mixture of literally typed and expressions producing a real number, together with another ordered collection of their multiplicative inverses. Try and use the following pseudo-code to generate the numbers for the ordered collections:
x = 2.0
xi = 0.5
y = 4.0
yi = 0.25
z = x + y
zi = 1.0 / ( x + y )
Create a function multiplier, that given two numbers as arguments returns a function that when called with one argument, returns the result of multiplying the two arguments to the call to multiplier that created it and the argument in the call:
new_function = multiplier(n1,n2)
# where new_function(m) returns the result of n1 * n2 * m
Applying the multiplier of a number and its inverse from the two ordered collections of numbers in pairs, show that the result in each case is one.
Compare and contrast the resultant program with the corresponding entry in First-class functions. They should be close.
To paraphrase the task description: Do what was done before, but with numbers rather than functions
|
#Fantom
|
Fantom
|
class Main
{
static |Float -> Float| combine (Float n1, Float n2)
{
return |Float m -> Float| { n1 * n2 * m }
}
public static Void main ()
{
Float x := 2f
Float xi := 0.5f
Float y := 4f
Float yi := 0.25f
Float z := x + y
Float zi := 1 / (x + y)
echo (combine(x, xi)(0.5f))
echo (combine(y, yi)(0.5f))
echo (combine(z, zi)(0.5f))
}
}
|
http://rosettacode.org/wiki/First-class_functions/Use_numbers_analogously
|
First-class functions/Use numbers analogously
|
In First-class functions, a language is showing how its manipulation of functions is similar to its manipulation of other types.
This tasks aim is to compare and contrast a language's implementation of first class functions, with its normal handling of numbers.
Write a program to create an ordered collection of a mixture of literally typed and expressions producing a real number, together with another ordered collection of their multiplicative inverses. Try and use the following pseudo-code to generate the numbers for the ordered collections:
x = 2.0
xi = 0.5
y = 4.0
yi = 0.25
z = x + y
zi = 1.0 / ( x + y )
Create a function multiplier, that given two numbers as arguments returns a function that when called with one argument, returns the result of multiplying the two arguments to the call to multiplier that created it and the argument in the call:
new_function = multiplier(n1,n2)
# where new_function(m) returns the result of n1 * n2 * m
Applying the multiplier of a number and its inverse from the two ordered collections of numbers in pairs, show that the result in each case is one.
Compare and contrast the resultant program with the corresponding entry in First-class functions. They should be close.
To paraphrase the task description: Do what was done before, but with numbers rather than functions
|
#Go
|
Go
|
package main
import "fmt"
func main() {
x := 2.
xi := .5
y := 4.
yi := .25
z := x + y
zi := 1 / (x + y)
// point A
numbers := []float64{x, y, z}
inverses := []float64{xi, yi, zi}
// point B
mfs := make([]func(float64) float64, len(numbers))
for i := range mfs {
mfs[i] = multiplier(numbers[i], inverses[i])
}
// point C
for _, mf := range mfs {
fmt.Println(mf(1))
}
}
func multiplier(n1, n2 float64) func(float64) float64 {
// compute product of n's, store in a new variable
n1n2 := n1 * n2
// close on variable containing product
return func(m float64) float64 {
return n1n2 * m
}
}
|
http://rosettacode.org/wiki/Flow-control_structures
|
Flow-control structures
|
Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
Document common flow-control structures.
One common example of a flow-control structure is the goto construct.
Note that Conditional Structures and Loop Structures have their own articles/categories.
Related tasks
Conditional Structures
Loop Structures
|
#Kotlin
|
Kotlin
|
// version 1.0.6
fun main(args: Array<String>) {
for (i in 0 .. 2) {
for (j in 0 .. 2) {
if (i + j == 2) continue
if (i + j == 3) break
println(i + j)
}
}
println()
if (args.isNotEmpty()) throw IllegalArgumentException("No command line arguments should be supplied")
println("Goodbye!") // won't be executed
}
|
http://rosettacode.org/wiki/Flow-control_structures
|
Flow-control structures
|
Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
Document common flow-control structures.
One common example of a flow-control structure is the goto construct.
Note that Conditional Structures and Loop Structures have their own articles/categories.
Related tasks
Conditional Structures
Loop Structures
|
#Lua
|
Lua
|
i = 0
while true do
i = i + 1
if i > 10 then break end
end
|
http://rosettacode.org/wiki/Floyd%27s_triangle
|
Floyd's triangle
|
Floyd's triangle lists the natural numbers in a right triangle aligned to the left where
the first row is 1 (unity)
successive rows start towards the left with the next number followed by successive naturals listing one more number than the line above.
The first few lines of a Floyd triangle looks like this:
1
2 3
4 5 6
7 8 9 10
11 12 13 14 15
Task
Write a program to generate and display here the first n lines of a Floyd triangle.
(Use n=5 and n=14 rows).
Ensure that when displayed in a mono-space font, the numbers line up in vertical columns as shown and that only one space separates numbers of the last row.
|
#C.2B.2B
|
C++
|
#include <windows.h>
#include <sstream>
#include <iostream>
//--------------------------------------------------------------------------------------------------
using namespace std;
//--------------------------------------------------------------------------------------------------
class floyds_tri
{
public:
floyds_tri() { lastLineLen = 0; }
~floyds_tri() { killArray(); }
void create( int rows )
{
_rows = rows;
calculateLastLineLen();
display();
}
private:
void killArray()
{
if( lastLineLen )
delete [] lastLineLen;
}
void calculateLastLineLen()
{
killArray();
lastLineLen = new BYTE[_rows];
int s = 1 + ( _rows * ( _rows - 1 ) ) / 2;
for( int x = s, ix = 0; x < s + _rows; x++, ix++ )
{
ostringstream cvr;
cvr << x;
lastLineLen[ix] = static_cast<BYTE>( cvr.str().size() );
}
}
void display()
{
cout << endl << "Floyd\'s Triangle - " << _rows << " rows" << endl << "===============================================" << endl;
int number = 1;
for( int r = 0; r < _rows; r++ )
{
for( int c = 0; c <= r; c++ )
{
ostringstream cvr;
cvr << number++;
string str = cvr.str();
while( str.length() < lastLineLen[c] )
str = " " + str;
cout << str << " ";
}
cout << endl;
}
}
int _rows;
BYTE* lastLineLen;
};
//--------------------------------------------------------------------------------------------------
int main( int argc, char* argv[] )
{
floyds_tri t;
int s;
while( true )
{
cout << "Enter the size of the triangle ( 0 to QUIT ): "; cin >> s;
if( !s ) return 0;
if( s > 0 ) t.create( s );
cout << endl << endl;
system( "pause" );
}
return 0;
}
//--------------------------------------------------------------------------------------------------
|
http://rosettacode.org/wiki/Floyd-Warshall_algorithm
|
Floyd-Warshall algorithm
|
The Floyd–Warshall algorithm is an algorithm for finding shortest paths in a weighted graph with positive or negative edge weights.
Task
Find the lengths of the shortest paths between all pairs of vertices of the given directed graph. Your code may assume that the input has already been checked for loops, parallel edges and negative cycles.
Print the pair, the distance and (optionally) the path.
Example
pair dist path
1 -> 2 -1 1 -> 3 -> 4 -> 2
1 -> 3 -2 1 -> 3
1 -> 4 0 1 -> 3 -> 4
2 -> 1 4 2 -> 1
2 -> 3 2 2 -> 1 -> 3
2 -> 4 4 2 -> 1 -> 3 -> 4
3 -> 1 5 3 -> 4 -> 2 -> 1
3 -> 2 1 3 -> 4 -> 2
3 -> 4 2 3 -> 4
4 -> 1 3 4 -> 2 -> 1
4 -> 2 -1 4 -> 2
4 -> 3 1 4 -> 2 -> 1 -> 3
See also
Floyd-Warshall Algorithm - step by step guide (youtube)
|
#JavaScript
|
JavaScript
|
var graph = [];
for (i = 0; i < 10; ++i) {
graph.push([]);
for (j = 0; j < 10; ++j)
graph[i].push(i == j ? 0 : 9999999);
}
for (i = 1; i < 10; ++i) {
graph[0][i] = graph[i][0] = parseInt(Math.random() * 9 + 1);
}
for (k = 0; k < 10; ++k) {
for (i = 0; i < 10; ++i) {
for (j = 0; j < 10; ++j) {
if (graph[i][j] > graph[i][k] + graph[k][j])
graph[i][j] = graph[i][k] + graph[k][j]
}
}
}
console.log(graph);
|
http://rosettacode.org/wiki/Function_definition
|
Function definition
|
A function is a body of code that returns a value.
The value returned may depend on arguments provided to the function.
Task
Write a definition of a function called "multiply" that takes two arguments and returns their product.
(Argument types should be chosen so as not to distract from showing how functions are created and values returned).
Related task
Function prototype
|
#Ring
|
Ring
|
func multiply x,y return x*y
|
http://rosettacode.org/wiki/Function_definition
|
Function definition
|
A function is a body of code that returns a value.
The value returned may depend on arguments provided to the function.
Task
Write a definition of a function called "multiply" that takes two arguments and returns their product.
(Argument types should be chosen so as not to distract from showing how functions are created and values returned).
Related task
Function prototype
|
#RLaB
|
RLaB
|
>> class(sin)
function
>> type(sin)
builtin
|
http://rosettacode.org/wiki/Forward_difference
|
Forward difference
|
Task
Provide code that produces a list of numbers which is the nth order forward difference, given a non-negative integer (specifying the order) and a list of numbers.
The first-order forward difference of a list of numbers A is a new list B, where Bn = An+1 - An.
List B should have one fewer element as a result.
The second-order forward difference of A will be:
tdefmodule Diff do
def forward(arr,i\\1) do
forward(arr,[],i)
end
def forward([_|[]],diffs,i) do
if i == 1 do
IO.inspect diffs
else
forward(diffs,[],i-1)
end
end
def forward([val1|[val2|vals]],diffs,i) do
forward([val2|vals],diffs++[val2-val1],i)
end
end
The same as the first-order forward difference of B.
That new list will have two fewer elements than A and one less than B.
The goal of this task is to repeat this process up to the desired order.
For a more formal description, see the related Mathworld article.
Algorithmic options
Iterate through all previous forward differences and re-calculate a new array each time.
Use this formula (from Wikipedia):
Δ
n
[
f
]
(
x
)
=
∑
k
=
0
n
(
n
k
)
(
−
1
)
n
−
k
f
(
x
+
k
)
{\displaystyle \Delta ^{n}[f](x)=\sum _{k=0}^{n}{n \choose k}(-1)^{n-k}f(x+k)}
(Pascal's Triangle may be useful for this option.)
|
#NetRexx
|
NetRexx
|
/* NetRexx*************************************************************
* Forward differences
* 18.08.2012 Walter Pachl derived from Rexx
**********************************************************************/
Loop n=-1 To 11
differences('90 47 58 29 22 32 55 5 55 73',n)
End
method differences(a,n) public static
--arr=Rexx[11] -- array must be declared (zero based)
arr='' -- alternative: indexed string
m=a.words
Select
When n<0 Then Say 'n is negative:' n '<' 0
When n>m Then Say 'n is too large:' n '>' m
Otherwise Do
Loop i=1 To m
arr[i]=a.word(i)
End
Loop i = 1 to n
t = arr[i]
Loop j = i+1 to m
u = arr[j]
arr[j] = arr[j]-t
t = u
end
end
ol=''
Loop i=n+1 to m
ol=ol arr[i]
End
Say n ol
End
End
|
http://rosettacode.org/wiki/Hello_world/Text
|
Hello world/Text
|
Hello world/Text is part of Short Circuit's Console Program Basics selection.
Task
Display the string Hello world! on a text console.
Related tasks
Hello world/Graphical
Hello world/Line Printer
Hello world/Newbie
Hello world/Newline omission
Hello world/Standard error
Hello world/Web server
|
#zkl
|
zkl
|
println("Hello world!");
|
http://rosettacode.org/wiki/Hello_world/Text
|
Hello world/Text
|
Hello world/Text is part of Short Circuit's Console Program Basics selection.
Task
Display the string Hello world! on a text console.
Related tasks
Hello world/Graphical
Hello world/Line Printer
Hello world/Newbie
Hello world/Newline omission
Hello world/Standard error
Hello world/Web server
|
#Zig
|
Zig
|
const std = @import("std");
pub fn main() !void {
try std.io.getStdOut().writer().writeAll("Hello world!\n");
}
|
http://rosettacode.org/wiki/Formatted_numeric_output
|
Formatted numeric output
|
Task
Express a number in decimal as a fixed-length string with leading zeros.
For example, the number 7.125 could be expressed as 00007.125.
|
#R
|
R
|
> sprintf("%f", pi)
[1] "3.141593"
> sprintf("%.3f", pi)
[1] "3.142"
> sprintf("%1.0f", pi)
[1] "3"
> sprintf("%5.1f", pi)
[1] " 3.1"
> sprintf("%05.1f", pi)
[1] "003.1"
> sprintf("%+f", pi)
[1] "+3.141593"
> sprintf("% f", pi)
[1] " 3.141593"
> sprintf("%-10f", pi)# left justified
[1] "3.141593 "
> sprintf("%e", pi)
[1] "3.141593e+00"
> sprintf("%E", pi)
[1] "3.141593E+00"
> sprintf("%g", pi)
[1] "3.14159"
> sprintf("%g", 1e6 * pi) # -> exponential
[1] "3.14159e+06"
> sprintf("%.9g", 1e6 * pi) # -> "fixed"
[1] "3141592.65"
> sprintf("%G", 1e-6 * pi)
[1] "3.14159E-06"
|
http://rosettacode.org/wiki/Formatted_numeric_output
|
Formatted numeric output
|
Task
Express a number in decimal as a fixed-length string with leading zeros.
For example, the number 7.125 could be expressed as 00007.125.
|
#Racket
|
Racket
|
-> (displayln (~a 7.125 #:width 9 #:align 'right #:pad-string "0"))
00007.125
|
http://rosettacode.org/wiki/Four_bit_adder
|
Four bit adder
|
Task
"Simulate" a four-bit adder.
This design can be realized using four 1-bit full adders.
Each of these 1-bit full adders can be built with two half adders and an or gate. ;
Finally a half adder can be made using an xor gate and an and gate.
The xor gate can be made using two nots, two ands and one or.
Not, or and and, the only allowed "gates" for the task, can be "imitated" by using the bitwise operators of your language.
If there is not a bit type in your language, to be sure that the not does not "invert" all the other bits of the basic type (e.g. a byte) we are not interested in, you can use an extra nand (and then not) with the constant 1 on one input.
Instead of optimizing and reducing the number of gates used for the final 4-bit adder, build it in the most straightforward way, connecting the other "constructive blocks", in turn made of "simpler" and "smaller" ones.
Schematics of the "constructive blocks"
(Xor gate with ANDs, ORs and NOTs)
(A half adder)
(A full adder)
(A 4-bit adder)
Solutions should try to be as descriptive as possible, making it as easy as possible to identify "connections" between higher-order "blocks".
It is not mandatory to replicate the syntax of higher-order blocks in the atomic "gate" blocks, i.e. basic "gate" operations can be performed as usual bitwise operations, or they can be "wrapped" in a block in order to expose the same syntax of higher-order blocks, at implementers' choice.
To test the implementation, show the sum of two four-bit numbers (in binary).
|
#Nim
|
Nim
|
type
Bools[N: static int] = array[N, bool]
SumCarry = tuple[sum, carry: bool]
proc ha(a, b: bool): SumCarry = (a xor b, a and b)
proc fa(a, b, ci: bool): SumCarry =
let a = ha(ci, a)
let b = ha(a[0], b)
result = (b[0], a[1] or b[1])
proc fa4(a, b: Bools[4]): Bools[5] =
var co, s: Bools[4]
for i in 0..3:
let r = fa(a[i], b[i], if i > 0: co[i-1] else: false)
s[i] = r[0]
co[i] = r[1]
result[0..3] = s
result[4] = co[3]
proc int2bus(n: int): Bools[4] =
var n = n
for i in 0..result.high:
result[i] = (n and 1) == 1
n = n shr 1
proc bus2int(b: Bools): int =
for i, x in b:
result += (if x: 1 else: 0) shl i
for a in 0..7:
for b in 0..7:
assert a + b == bus2int fa4(int2bus(a), int2bus(b))
|
http://rosettacode.org/wiki/Fivenum
|
Fivenum
|
Many big data or scientific programs use boxplots to show distributions of data. In addition, sometimes saving large arrays for boxplots can be impractical and use extreme amounts of RAM. It can be useful to save large arrays as arrays with five numbers to save memory.
For example, the R programming language implements Tukey's five-number summary as the fivenum function.
Task
Given an array of numbers, compute the five-number summary.
Note
While these five numbers can be used to draw a boxplot, statistical packages will typically need extra data.
Moreover, while there is a consensus about the "box" of the boxplot, there are variations among statistical packages for the whiskers.
|
#C.2B.2B
|
C++
|
#include <algorithm>
#include <iostream>
#include <ostream>
#include <vector>
/////////////////////////////////////////////////////////////////////////////
// The following is taken from https://cpplove.blogspot.com/2012/07/printing-tuples.html
// Define a type which holds an unsigned integer value
template<std::size_t> struct int_ {};
template <class Tuple, size_t Pos>
std::ostream& print_tuple(std::ostream& out, const Tuple& t, int_<Pos>) {
out << std::get< std::tuple_size<Tuple>::value - Pos >(t) << ", ";
return print_tuple(out, t, int_<Pos - 1>());
}
template <class Tuple>
std::ostream& print_tuple(std::ostream& out, const Tuple& t, int_<1>) {
return out << std::get<std::tuple_size<Tuple>::value - 1>(t);
}
template <class... Args>
std::ostream& operator<<(std::ostream& out, const std::tuple<Args...>& t) {
out << '(';
print_tuple(out, t, int_<sizeof...(Args)>());
return out << ')';
}
/////////////////////////////////////////////////////////////////////////////
template <class RI>
double median(RI beg, RI end) {
if (beg == end) throw std::runtime_error("Range cannot be empty");
auto len = end - beg;
auto m = len / 2;
if (len % 2 == 1) {
return *(beg + m);
}
return (beg[m - 1] + beg[m]) / 2.0;
}
template <class C>
auto fivenum(C& c) {
std::sort(c.begin(), c.end());
auto cbeg = c.cbegin();
auto cend = c.cend();
auto len = cend - cbeg;
auto m = len / 2;
auto lower = (len % 2 == 1) ? m : m - 1;
double r2 = median(cbeg, cbeg + lower + 1);
double r3 = median(cbeg, cend);
double r4 = median(cbeg + lower + 1, cend);
return std::make_tuple(*cbeg, r2, r3, r4, *(cend - 1));
}
int main() {
using namespace std;
vector<vector<double>> cs = {
{ 15.0, 6.0, 42.0, 41.0, 7.0, 36.0, 49.0, 40.0, 39.0, 47.0, 43.0 },
{ 36.0, 40.0, 7.0, 39.0, 41.0, 15.0 },
{
0.14082834, 0.09748790, 1.73131507, 0.87636009, -1.95059594, 0.73438555,
-0.03035726, 1.46675970, -0.74621349, -0.72588772, 0.63905160, 0.61501527,
-0.98983780, -1.00447874, -0.62759469, 0.66206163, 1.04312009, -0.10305385,
0.75775634, 0.32566578
}
};
for (auto & c : cs) {
cout << fivenum(c) << endl;
}
return 0;
}
|
http://rosettacode.org/wiki/FizzBuzz
|
FizzBuzz
|
Task
Write a program that prints the integers from 1 to 100 (inclusive).
But:
for multiples of three, print Fizz (instead of the number)
for multiples of five, print Buzz (instead of the number)
for multiples of both three and five, print FizzBuzz (instead of the number)
The FizzBuzz problem was presented as the lowest level of comprehension required to illustrate adequacy.
Also see
(a blog) dont-overthink-fizzbuzz
(a blog) fizzbuzz-the-programmers-stairway-to-heaven
|
#11l
|
11l
|
L(i) 1..100
I i % 15 == 0
print(‘FizzBuzz’)
E I i % 3 == 0
print(‘Fizz’)
E I i % 5 == 0
print(‘Buzz’)
E
print(i)
|
http://rosettacode.org/wiki/Five_weekends
|
Five weekends
|
The month of October in 2010 has five Fridays, five Saturdays, and five Sundays.
Task
Write a program to show all months that have this same characteristic of five full weekends from the year 1900 through 2100 (Gregorian calendar).
Show the number of months with this property (there should be 201).
Show at least the first and last five dates, in order.
Algorithm suggestions
Count the number of Fridays, Saturdays, and Sundays in every month.
Find all of the 31-day months that begin on Friday.
Extra credit
Count and/or show all of the years which do not have at least one five-weekend month (there should be 29).
Related tasks
Day of the week
Last Friday of each month
Find last sunday of each month
|
#360_Assembly
|
360 Assembly
|
* Five weekends 31/05/2016
FIVEWEEK CSECT
USING FIVEWEEK,R13 base register
B 72(R15) skip savearea
DC 17F'0' savearea
STM R14,R12,12(R13) prolog
ST R13,4(R15) "
ST R15,8(R13) "
LR R13,R15 "
LM R10,R11,=AL8(0) nko=0; nok=0
LH R6,Y1 y=y1
LOOPY CH R6,Y2 do y=y1 to y2
BH ELOOPY
MVI YF,X'00' yf=0
LA R7,1 im=1
LOOPIM C R7,=F'7' do im=1 to 7
BH ELOOPIM
LR R1,R7 im
SLA R1,1 *2 (H)
LH R2,ML-2(R1) ml(im)
ST R2,M m=ml(im)
MVC D,=F'1' d=1
L R4,M m
C R4,=F'2' if m<=2
BH MSUP2
L R8,M m
LA R8,12(R8) mw=m+12
LR R9,R6 y
BCTR R9,0 yw=y-1
B EMSUP2
MSUP2 L R8,M mw=m
LR R9,R6 yw=y
EMSUP2 LR R4,R9 ym
SRDA R4,32 .
D R4,=F'100' yw/100
ST R5,J j=yw/100
ST R4,K k=yw//100
LR R4,R8 mw
LA R4,1(R4) mw+1
MH R4,=H'26' (mw+1)*26
SRDA R4,32 .
D R4,=F'10' (mw+1)*26/10
LR R2,R5 "
A R2,D d
A R2,K d+k
L R3,K k
SRA R3,2 k/4
AR R2,R3 (mw+1)*26/10+k/4
L R3,J j
SRA R3,2 j/4
AR R2,R3 (mw+1)*26/10+k/4+j/4
LA R5,5 5
M R4,J 5*j
AR R2,R5 (mw+1)*26/10+k/4+j/4
SRDA R2,32 .
D R2,=F'7' (d+(mw+1)*26/10+k+k/4+j/4+5*j)/7
C R2,=F'6' if dow=friday
BNE NOFRIDAY
XDECO R6,XDEC y
MVC PG+0(4),XDEC+8 output y
LR R1,R7 im
MH R1,=H'3' *3
LA R14,MN-3(R1) @mn(im)
MVC PG+5(3),0(R14) output mn(im)
XPRNT PG,8 print buffer
LA R11,1(R11) nok=nok+1
MVI YF,X'01' yf=1
NOFRIDAY LA R7,1(R7) im=im+1
B LOOPIM
ELOOPIM L R4,YF yf
CLI YF,X'00' if yf=0
BNE EYFNE0
LA R10,1(R10) nko=nko+1
EYFNE0 LA R6,1(R6) y=y+1
B LOOPY
ELOOPY XDECO R11,XDEC nok
MVC PG+0(4),XDEC+8 output nok
MVC PG+4(12),=C' occurrences'
XPRNT PG,80 print buffer
XDECO R10,XDEC nko
MVC PG+0(4),XDEC+8 output nko
MVC PG+4(33),=C' years with no five weekend month'
XPRNT PG,80 print buffer
L R13,4(0,R13) epilog
LM R14,R12,12(R13) "
XR R15,R15 "
BR R14 exit
Y1 DC H'1900' year start
Y2 DC H'2100' year stop
ML DC H'1',H'3',H'5',H'7',H'8',H'10',H'12'
MN DC C'jan',C'mar',C'may',C'jul',C'aug',C'oct',C'dec'
YF DS X year flag
M DS F month
D DS F day
J DS F j=yw/100
K DS F j=mod(yw,100)
PG DC CL80'....-' buffer
XDEC DS CL12 temp for XDECO
YREGS
END FIVEWEEK
|
http://rosettacode.org/wiki/First_perfect_square_in_base_n_with_n_unique_digits
|
First perfect square in base n with n unique digits
|
Find the first perfect square in a given base N that has at least N digits and
exactly N significant unique digits when expressed in base N.
E.G. In base 10, the first perfect square with at least 10 unique digits is 1026753849 (32043²).
You may use analytical methods to reduce the search space, but the code must do a search. Do not use magic numbers or just feed the code the answer to verify it is correct.
Task
Find and display here, on this page, the first perfect square in base N, with N significant unique digits when expressed in base N, for each of base 2 through 12. Display each number in the base N for which it was calculated.
(optional) Do the same for bases 13 through 16.
(stretch goal) Continue on for bases 17 - ?? (Big Integer math)
See also
OEIS A260182: smallest square that is pandigital in base n.
Related task
Casting out nines
|
#11l
|
11l
|
L(base) 2..16
V n = Int64(Float(base) ^ ((base - 1) / 2))
L
V sq = n * n
V sqstr = String(sq, radix' base)
I sqstr.len >= base & Set(Array(sqstr)).len == base
V nstr = String(n, radix' base)
print(‘Base #2: #8^2 = #.’.format(base, nstr, sqstr))
L.break
n++
|
http://rosettacode.org/wiki/First-class_functions
|
First-class functions
|
A language has first-class functions if it can do each of the following without recursively invoking a compiler or interpreter or otherwise metaprogramming:
Create new functions from preexisting functions at run-time
Store functions in collections
Use functions as arguments to other functions
Use functions as return values of other functions
Task
Write a program to create an ordered collection A of functions of a real number. At least one function should be built-in and at least one should be user-defined; try using the sine, cosine, and cubing functions. Fill another collection B with the inverse of each function in A. Implement function composition as in Functional Composition. Finally, demonstrate that the result of applying the composition of each function in A and its inverse in B to a value, is the original value. (Within the limits of computational accuracy).
(A solution need not actually call the collections "A" and "B". These names are only used in the preceding paragraph for clarity.)
Related task
First-class Numbers
|
#Aikido
|
Aikido
|
import math
function compose (f, g) {
return function (x) { return f(g(x)) }
}
var fn = [Math.sin, Math.cos, function(x) { return x*x*x }]
var inv = [Math.asin, Math.acos, function(x) { return Math.pow(x, 1.0/3) }]
for (var i=0; i<3; i++) {
var f = compose(inv[i], fn[i])
println(f(0.5)) // 0.5
}
|
http://rosettacode.org/wiki/First-class_functions
|
First-class functions
|
A language has first-class functions if it can do each of the following without recursively invoking a compiler or interpreter or otherwise metaprogramming:
Create new functions from preexisting functions at run-time
Store functions in collections
Use functions as arguments to other functions
Use functions as return values of other functions
Task
Write a program to create an ordered collection A of functions of a real number. At least one function should be built-in and at least one should be user-defined; try using the sine, cosine, and cubing functions. Fill another collection B with the inverse of each function in A. Implement function composition as in Functional Composition. Finally, demonstrate that the result of applying the composition of each function in A and its inverse in B to a value, is the original value. (Within the limits of computational accuracy).
(A solution need not actually call the collections "A" and "B". These names are only used in the preceding paragraph for clarity.)
Related task
First-class Numbers
|
#ALGOL_68
|
ALGOL 68
|
MODE F = PROC (REAL)REAL;
OP ** = (REAL x, power)REAL: exp(ln(x)*power);
# Add a user defined function and its inverse #
PROC cube = (REAL x)REAL: x * x * x;
PROC cube root = (REAL x)REAL: x ** (1/3);
# First class functions allow run-time creation of functions from functions #
# return function compose(f,g)(x) == f(g(x)) #
PROC non standard compose = (F f1, f2)F: (REAL x)REAL: f1(f2(x)); # eg ELLA ALGOL 68RS #
PROC compose = (F f, g)F: ((F f2, g2, REAL x)REAL: f2(g2(x)))(f, g, );
# Or the classic "o" functional operator #
PRIO O = 5;
OP (F,F)F O = compose;
# first class functions should be able to be members of collection types #
[]F func list = (sin, cos, cube);
[]F arc func list = (arc sin, arc cos, cube root);
# Apply functions from lists as easily as integers #
FOR index TO UPB func list DO
STRUCT(F f, inverse f) this := (func list[index], arc func list[index]);
print(((inverse f OF this O f OF this)(.5), new line))
OD
|
http://rosettacode.org/wiki/Forest_fire
|
Forest fire
|
This page uses content from Wikipedia. The original article was at Forest-fire model. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
Task
Implement the Drossel and Schwabl definition of the forest-fire model.
It is basically a 2D cellular automaton where each cell can be in three distinct states (empty, tree and burning) and evolves according to the following rules (as given by Wikipedia)
A burning cell turns into an empty cell
A tree will burn if at least one neighbor is burning
A tree ignites with probability f even if no neighbor is burning
An empty space fills with a tree with probability p
Neighborhood is the Moore neighborhood; boundary conditions are so that on the boundary the cells are always empty ("fixed" boundary condition).
At the beginning, populate the lattice with empty and tree cells according to a specific probability (e.g. a cell has the probability 0.5 to be a tree). Then, let the system evolve.
Task's requirements do not include graphical display or the ability to change parameters (probabilities p and f ) through a graphical or command line interface.
Related tasks
See Conway's Game of Life
See Wireworld.
|
#EasyLang
|
EasyLang
|
p_fire = 0.00002
p_tree = 0.002
#
len f[] 102 * 102
len p[] len f[]
background 100
clear
for r range 100
for c range 100
i = r * 102 + c + 103
if randomf < 0.5
f[i] = 1
.
.
.
timer 0
#
subr show
for r range 100
for c range 100
i = r * 102 + c + 103
h = f[i]
if h <> p[i]
move c + 0.5 r + 0.5
if h = 0
color 100
circle 0.6
elif h = 1
color 151
circle 0.5
else
color 9 * 100 + (18 - 2 * h) * 10
circle 0.5
.
.
.
.
.
subr update
swap f[] p[]
for r range 100
for c range 100
i = r * 102 + c + 103
if p[i] = 0
f[i] = 0
if randomf < p_tree
f[i] = 1
.
elif p[i] = 1
f[i] = 1
s = p[i - 103] + p[i - 102] + p[i - 101]
s += p[i - 1] + p[i + 1]
s += p[i + 101] + p[i + 102] + p[i + 103]
if s >= 9 or randomf < p_fire
f[i] = 9
.
elif p[i] = 4
f[i] = 0
else
f[i] = p[i] - 1
.
.
.
.
on timer
call show
call update
timer 0.2
.
|
http://rosettacode.org/wiki/First_class_environments
|
First class environments
|
According to Wikipedia, "In computing, a first-class object ... is an entity that can be constructed at run-time, passed as a parameter, returned from a subroutine, or assigned into a variable".
Often this term is used in the context of "first class functions". In an analogous way, a programming language may support "first class environments".
The environment is minimally, the set of variables accessible to a statement being executed. Change the environments and the same statement could produce different results when executed.
Often an environment is captured in a closure, which encapsulates a function together with an environment. That environment, however, is not first-class, as it cannot be created, passed etc. independently from the function's code.
Therefore, a first class environment is a set of variable bindings which can be constructed at run-time, passed as a parameter, returned from a subroutine, or assigned into a variable. It is like a closure without code. A statement must be able to be executed within a stored first class environment and act according to the environment variable values stored within.
Task
Build a dozen environments, and a single piece of code to be run repeatedly in each of these environments.
Each environment contains the bindings for two variables:
a value in the Hailstone sequence, and
a count which is incremented until the value drops to 1.
The initial hailstone values are 1 through 12, and the count in each environment is zero.
When the code runs, it calculates the next hailstone step in the current environment (unless the value is already 1) and counts the steps. Then it prints the current value in a tabular form.
When all hailstone values dropped to 1, processing stops, and the total number of hailstone steps for each environment is printed.
|
#EchoLisp
|
EchoLisp
|
(define (bump-value)
(when (> value 1)
(set! count (1+ count))
(set! value (if (even? value) (/ value 2) (1+ (* 3 value))))))
(define (env-show name envs )
(write name)
(for ((env envs)) (write (format "%4a" (eval name env))))
(writeln))
(define (task (envnum 12))
(define envs (for/list ((i envnum)) (environment-new `((value ,(1+ i)) (count 0)))))
(env-show 'value envs)
(while
(any (curry (lambda ( n env) (!= 1 (eval n env))) 'value) envs)
(for/list ((env envs)) (eval '(bump-value) env))
(env-show 'value envs))
(env-show 'count envs))
|
http://rosettacode.org/wiki/First_class_environments
|
First class environments
|
According to Wikipedia, "In computing, a first-class object ... is an entity that can be constructed at run-time, passed as a parameter, returned from a subroutine, or assigned into a variable".
Often this term is used in the context of "first class functions". In an analogous way, a programming language may support "first class environments".
The environment is minimally, the set of variables accessible to a statement being executed. Change the environments and the same statement could produce different results when executed.
Often an environment is captured in a closure, which encapsulates a function together with an environment. That environment, however, is not first-class, as it cannot be created, passed etc. independently from the function's code.
Therefore, a first class environment is a set of variable bindings which can be constructed at run-time, passed as a parameter, returned from a subroutine, or assigned into a variable. It is like a closure without code. A statement must be able to be executed within a stored first class environment and act according to the environment variable values stored within.
Task
Build a dozen environments, and a single piece of code to be run repeatedly in each of these environments.
Each environment contains the bindings for two variables:
a value in the Hailstone sequence, and
a count which is incremented until the value drops to 1.
The initial hailstone values are 1 through 12, and the count in each environment is zero.
When the code runs, it calculates the next hailstone step in the current environment (unless the value is already 1) and counts the steps. Then it prints the current value in a tabular form.
When all hailstone values dropped to 1, processing stops, and the total number of hailstone steps for each environment is printed.
|
#Erlang
|
Erlang
|
Note that using the Process Dictionary:
Destroys referencial transparency
Makes debugging difficult
Survives Catch/Throw
|
http://rosettacode.org/wiki/Flatten_a_list
|
Flatten a list
|
Task
Write a function to flatten the nesting in an arbitrary list of values.
Your program should work on the equivalent of this list:
[[1], 2, [[3, 4], 5], [[[]]], [[[6]]], 7, 8, []]
Where the correct result would be the list:
[1, 2, 3, 4, 5, 6, 7, 8]
Related task
Tree traversal
|
#C.23
|
C#
|
using System;
using System.Collections;
using System.Linq;
namespace RosettaCodeTasks
{
static class FlattenList
{
public static ArrayList Flatten(this ArrayList List)
{
ArrayList NewList = new ArrayList ( );
NewList.AddRange ( List );
while ( NewList.OfType<ArrayList> ( ).Count ( ) > 0 )
{
int index = NewList.IndexOf ( NewList.OfType<ArrayList> ( ).ElementAt ( 0 ) );
ArrayList Temp = (ArrayList)NewList[index];
NewList.RemoveAt ( index );
NewList.InsertRange ( index, Temp );
}
return NewList;
}
}
}
|
http://rosettacode.org/wiki/Flipping_bits_game
|
Flipping bits game
|
The game
Given an N×N square array of zeroes or ones in an initial configuration, and a target configuration of zeroes and ones.
The game is to transform one to the other in as few moves as possible by inverting whole numbered rows or whole lettered
columns at once (as one move).
In an inversion. any 1 becomes 0, and any 0 becomes 1 for that whole row or column.
Task
Create a program to score for the Flipping bits game.
The game should create an original random target configuration and a starting configuration.
Ensure that the starting position is never the target position.
The target position must be guaranteed as reachable from the starting position. (One possible way to do this is to generate the start position by legal flips from a random target position. The flips will always be reversible back to the target from the given start position).
The number of moves taken so far should be shown.
Show an example of a short game here, on this page, for a 3×3 array of bits.
|
#Julia
|
Julia
|
module FlippingBitsGame
using Printf, Random
import Base.size, Base.show, Base.==
struct Configuration
M::BitMatrix
end
Base.size(c::Configuration) = size(c.M)
function Base.show(io::IO, conf::Configuration)
M = conf.M
nrow, ncol = size(M)
print(io, " " ^ 3)
for c in 1:ncol
@printf(io, "%3i", c)
end
println(io, "\n", " " ^ 4, "-" ^ 3ncol)
for r in 1:nrow
@printf(io, "%2i |", r)
for c in 1:ncol
@printf(io, "%2c ", ifelse(M[r, c], 'T', 'F'))
end
println(io)
end
return nothing
end
Base.:(==)(a::Configuration, b::Configuration) = a.M == b.M
struct Index{D}
i::Int
end
const ColIndex = Index{:C}
const RowIndex = Index{:R}
function flipbits!(conf::Configuration, c::ColIndex)
col = @view conf.M[:, c.i]
@. col = !col
return conf
end
function flipbits!(conf::Configuration, r::RowIndex)
row = @view conf.M[r.i, :]
@. row = !row
return conf
end
randomconfig(nrow::Integer, ncol::Integer) = Configuration(bitrand(nrow, ncol))
function randommoves!(conf::Configuration, nflips::Integer)
nrow, ncol = size(conf)
for _ in Base.OneTo(nflips)
if rand() < 0.5
flipbits!(conf, ColIndex(rand(1:ncol)))
else
flipbits!(conf, RowIndex(rand(1:nrow)))
end
end
return conf
end
function play()
nrow::Int, ncol::Int = 0, 0
while nrow < 2 || ncol < 2
print("Insert the size of the matrix (nrow [> 1] *space* ncol [> 1]):")
nrow, ncol = parse.(Int, split(readline()))
end
mat = randomconfig(nrow, ncol)
obj = deepcopy(mat)
randommoves!(obj, 100)
nflips = 0
while mat != obj
println("\n", nflips, " flips until now.")
println("Current configuration:")
println(mat)
println("Objective configuration:")
println(obj)
print("Insert R[ind] to flip row, C[ind] to flip a column, Q to quit: ")
line = readline()
input = match(r"([qrc])(\d+)"i, line)
if input ≢ nothing && all(input.captures .≢ nothing)
dim = Symbol(uppercase(input.captures[1]))
ind = Index{dim}(parse(Int, input.captures[2]))
flipbits!(mat, ind)
nflips += 1
elseif occursin("q", line)
println("\nSEE YOU SOON!")
return
else
println("\nINPUT NOT VALID, RETRY!\n")
end
end
println("\nSUCCED! In ", nflips, " flips.")
println(mat)
return
end
end # module FlippingBitsGame
using .FlippingBitsGame
FlippingBitsGame.play()
|
http://rosettacode.org/wiki/First_power_of_2_that_has_leading_decimal_digits_of_12
|
First power of 2 that has leading decimal digits of 12
|
(This task is taken from a Project Euler problem.)
(All numbers herein are expressed in base ten.)
27 = 128 and 7 is
the first power of 2 whose leading decimal digits are 12.
The next power of 2 whose leading decimal digits
are 12 is 80,
280 = 1208925819614629174706176.
Define p(L,n) to be the nth-smallest
value of j such that the base ten representation
of 2j begins with the digits of L .
So p(12, 1) = 7 and
p(12, 2) = 80
You are also given that:
p(123, 45) = 12710
Task
find:
p(12, 1)
p(12, 2)
p(123, 45)
p(123, 12345)
p(123, 678910)
display the results here, on this page.
|
#Go
|
Go
|
package main
import (
"fmt"
"math"
"time"
)
const ld10 = math.Ln2 / math.Ln10
func commatize(n uint64) string {
s := fmt.Sprintf("%d", n)
le := len(s)
for i := le - 3; i >= 1; i -= 3 {
s = s[0:i] + "," + s[i:]
}
return s
}
func p(L, n uint64) uint64 {
i := L
digits := uint64(1)
for i >= 10 {
digits *= 10
i /= 10
}
count := uint64(0)
for i = 0; count < n; i++ {
e := math.Exp(math.Ln10 * math.Mod(float64(i)*ld10, 1))
if uint64(math.Trunc(e*float64(digits))) == L {
count++
}
}
return i - 1
}
func main() {
start := time.Now()
params := [][2]uint64{{12, 1}, {12, 2}, {123, 45}, {123, 12345}, {123, 678910}}
for _, param := range params {
fmt.Printf("p(%d, %d) = %s\n", param[0], param[1], commatize(p(param[0], param[1])))
}
fmt.Printf("\nTook %s\n", time.Since(start))
}
|
http://rosettacode.org/wiki/First-class_functions/Use_numbers_analogously
|
First-class functions/Use numbers analogously
|
In First-class functions, a language is showing how its manipulation of functions is similar to its manipulation of other types.
This tasks aim is to compare and contrast a language's implementation of first class functions, with its normal handling of numbers.
Write a program to create an ordered collection of a mixture of literally typed and expressions producing a real number, together with another ordered collection of their multiplicative inverses. Try and use the following pseudo-code to generate the numbers for the ordered collections:
x = 2.0
xi = 0.5
y = 4.0
yi = 0.25
z = x + y
zi = 1.0 / ( x + y )
Create a function multiplier, that given two numbers as arguments returns a function that when called with one argument, returns the result of multiplying the two arguments to the call to multiplier that created it and the argument in the call:
new_function = multiplier(n1,n2)
# where new_function(m) returns the result of n1 * n2 * m
Applying the multiplier of a number and its inverse from the two ordered collections of numbers in pairs, show that the result in each case is one.
Compare and contrast the resultant program with the corresponding entry in First-class functions. They should be close.
To paraphrase the task description: Do what was done before, but with numbers rather than functions
|
#Groovy
|
Groovy
|
def multiplier = { n1, n2 -> { m -> n1 * n2 * m } }
def ε = 0.00000001 // tolerance(epsilon): acceptable level of "wrongness" to account for rounding error
[(2.0):0.5, (4.0):0.25, (6.0):(1/6.0)].each { num, inv ->
def new_function = multiplier(num, inv)
(1.0..5.0).each { trial ->
assert (new_function(trial) - trial).abs() < ε
printf('%5.3f * %5.3f * %5.3f == %5.3f\n', num, inv, trial, trial)
}
println()
}
|
http://rosettacode.org/wiki/First-class_functions/Use_numbers_analogously
|
First-class functions/Use numbers analogously
|
In First-class functions, a language is showing how its manipulation of functions is similar to its manipulation of other types.
This tasks aim is to compare and contrast a language's implementation of first class functions, with its normal handling of numbers.
Write a program to create an ordered collection of a mixture of literally typed and expressions producing a real number, together with another ordered collection of their multiplicative inverses. Try and use the following pseudo-code to generate the numbers for the ordered collections:
x = 2.0
xi = 0.5
y = 4.0
yi = 0.25
z = x + y
zi = 1.0 / ( x + y )
Create a function multiplier, that given two numbers as arguments returns a function that when called with one argument, returns the result of multiplying the two arguments to the call to multiplier that created it and the argument in the call:
new_function = multiplier(n1,n2)
# where new_function(m) returns the result of n1 * n2 * m
Applying the multiplier of a number and its inverse from the two ordered collections of numbers in pairs, show that the result in each case is one.
Compare and contrast the resultant program with the corresponding entry in First-class functions. They should be close.
To paraphrase the task description: Do what was done before, but with numbers rather than functions
|
#Haskell
|
Haskell
|
module Main
where
import Text.Printf
-- Pseudo code happens to be valid Haskell
x = 2.0
xi = 0.5
y = 4.0
yi = 0.25
z = x + y
zi = 1.0 / ( x + y )
-- Multiplier function
multiplier :: Double -> Double -> Double -> Double
multiplier a b = \m -> a * b * m
main :: IO ()
main = do
let
numbers = [x, y, z]
inverses = [xi, yi, zi]
pairs = zip numbers inverses
print_pair (number, inverse) =
let new_function = multiplier number inverse
in printf "%f * %f * 0.5 = %f\n" number inverse (new_function 0.5)
mapM_ print_pair pairs
|
http://rosettacode.org/wiki/Flow-control_structures
|
Flow-control structures
|
Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
Document common flow-control structures.
One common example of a flow-control structure is the goto construct.
Note that Conditional Structures and Loop Structures have their own articles/categories.
Related tasks
Conditional Structures
Loop Structures
|
#Mathematica_.2F_Wolfram_Language
|
Mathematica / Wolfram Language
|
try
% do some stuff
catch
% in case of error, continue here
end
|
http://rosettacode.org/wiki/Flow-control_structures
|
Flow-control structures
|
Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
Document common flow-control structures.
One common example of a flow-control structure is the goto construct.
Note that Conditional Structures and Loop Structures have their own articles/categories.
Related tasks
Conditional Structures
Loop Structures
|
#MATLAB_.2F_Octave
|
MATLAB / Octave
|
try
% do some stuff
catch
% in case of error, continue here
end
|
http://rosettacode.org/wiki/Floyd%27s_triangle
|
Floyd's triangle
|
Floyd's triangle lists the natural numbers in a right triangle aligned to the left where
the first row is 1 (unity)
successive rows start towards the left with the next number followed by successive naturals listing one more number than the line above.
The first few lines of a Floyd triangle looks like this:
1
2 3
4 5 6
7 8 9 10
11 12 13 14 15
Task
Write a program to generate and display here the first n lines of a Floyd triangle.
(Use n=5 and n=14 rows).
Ensure that when displayed in a mono-space font, the numbers line up in vertical columns as shown and that only one space separates numbers of the last row.
|
#Clojure
|
Clojure
|
(defn TriangleList [n]
(let [l (map inc (range))]
(loop [l l x 1 nl []]
(if (= n (count nl))
nl
(recur (drop x l) (inc x) (conj nl (take x l)))))))
(defn TrianglePrint [n]
(let [t (TriangleList n)
m (count (str (last (last t))))
f (map #(map str %) t)
l (map #(map (fn [x] (if (> m (count x))
(str (apply str (take (- m (count x))
(repeat " "))) x)
x)) %) f)
e (map #(map (fn [x] (str " " x)) %) l)]
(map #(println (apply str %)) e)))
|
http://rosettacode.org/wiki/Floyd-Warshall_algorithm
|
Floyd-Warshall algorithm
|
The Floyd–Warshall algorithm is an algorithm for finding shortest paths in a weighted graph with positive or negative edge weights.
Task
Find the lengths of the shortest paths between all pairs of vertices of the given directed graph. Your code may assume that the input has already been checked for loops, parallel edges and negative cycles.
Print the pair, the distance and (optionally) the path.
Example
pair dist path
1 -> 2 -1 1 -> 3 -> 4 -> 2
1 -> 3 -2 1 -> 3
1 -> 4 0 1 -> 3 -> 4
2 -> 1 4 2 -> 1
2 -> 3 2 2 -> 1 -> 3
2 -> 4 4 2 -> 1 -> 3 -> 4
3 -> 1 5 3 -> 4 -> 2 -> 1
3 -> 2 1 3 -> 4 -> 2
3 -> 4 2 3 -> 4
4 -> 1 3 4 -> 2 -> 1
4 -> 2 -1 4 -> 2
4 -> 3 1 4 -> 2 -> 1 -> 3
See also
Floyd-Warshall Algorithm - step by step guide (youtube)
|
#jq
|
jq
|
def weights: {
"1": {"3": -2},
"2": {"1" : 4, "3": 3},
"3": {"4": 2},
"4": {"2": -1}
};
|
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