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import java.util.PriorityQueue;
import java.util.Scanner;
import java.util.Comparator;
// basic tree structure for huffman coding
// Node class
class HuffNode{
int data;
char c;
HuffNode left;
HuffNode right;
}
// comparator class
// It compares the node
class MyComparator implements Comparator<HuffNode>{
public int compare(HuffNode x, HuffNode y){
return x.data-y.data;
}
}
public class HuffmanEncoding{
// recursive function to print the nodes
public static void printCode(HuffNode root, String s){
if(root.left==null && root.right==null && Character.isLetter(root.c)){
System.out.println(root.c+":"+s);
return;
}
printCode(root.left,s+"0");
printCode(root.right,s+"1");
}
public static void main(String[] args){
int n = 6;
char charArray[] = {'a','b','c','d','e','f'};
char frequency[] = {5,9,12,13,16,45};
PriorityQueue<HuffNode> q = new PriorityQueue<HuffNode>(n, new MyComparator());
for(int i=0;i<n;i++){
HuffNode hn = new HuffNode();
hn.c = charArray[i];
hn.data = frequency[i];
hn.right = null;
q.add(hn);
}
// create a root node
HuffNode root = null;
// now we extract the two minimum value
while(q.size() >1){
HuffNode x = q.peek();
q.poll();
HuffNode y = q.peek();
q.poll();
HuffNode f = new HuffNode();
f.data = x.data+y.data;
f.c = '-';
f.left = x;
f.right= y;
root = f;
q.add(f);
}
printCode(root,"");
}
}
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