File size: 2,357 Bytes
bc20498 |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 |
const nodeFrom = value => ({ value, next: null, prev: null });
const add = ( prev, node, next, list ) => {
if( prev !== null ){
prev.next = node;
} else {
list.head = node;
}
if( next !== null ){
next.prev = node;
} else {
list.tail = node;
}
node.prev = prev;
node.next = next;
list.length++;
return node;
};
const remove = ( node, list ) => {
let { prev, next } = node;
if( prev !== null ){
prev.next = next;
} else {
list.head = next;
}
if( next !== null ){
next.prev = prev;
} else {
list.tail = prev;
}
node.prev = node.next = null;
list.length--;
return node;
};
class LinkedList {
constructor( vals ){
this.length = 0;
this.head = null;
this.tail = null;
if( vals != null ){
vals.forEach( v => this.push(v) );
}
}
size(){
return this.length;
}
insertBefore( val, otherNode ){
return add( otherNode.prev, nodeFrom(val), otherNode, this );
}
insertAfter( val, otherNode ){
return add( otherNode, nodeFrom(val), otherNode.next, this );
}
insertNodeBefore( newNode, otherNode ){
return add( otherNode.prev, newNode, otherNode, this );
}
insertNodeAfter( newNode, otherNode ){
return add( otherNode, newNode, otherNode.next, this );
}
push( val ){
return add( this.tail, nodeFrom(val), null, this );
}
unshift( val ){
return add( null, nodeFrom(val), this.head, this );
}
remove( node ){
return remove( node, this );
}
pop(){
return remove( this.tail, this ).value;
}
popNode(){
return remove( this.tail, this );
}
shift(){
return remove( this.head, this ).value;
}
shiftNode(){
return remove( this.head, this );
}
get_object_at( index ){
if(index <= this.length()){
var i = 1;
var current = this.head;
while(i < index){
current = current.next;
i++;
}
return current.value;
}
}
set_object_at( index, value){
if(index <= this.length()) {
var i = 1;
var current = this.head;
while (i < index) {
current = current.next;
i++;
}
current.value = value;
}
}
}
module.exports = LinkedList;
|