algorithms/Java/HuffmanCoding.java at master · AASF-IIITM/algorithms · GitHub

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import java.util.PriorityQueue;
import java.util.Scanner;
import java.util.Comparator;


class HuffmanNode {

	int data;
	char c;

	HuffmanNode left;
	HuffmanNode right;
}


class MyComparator implements Comparator<HuffmanNode> {
	public int compare(HuffmanNode x, HuffmanNode y)
	{

		return x.data - y.data;
	}
}

public class Huffman {


	public static void printCode(HuffmanNode 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)
	{

		Scanner s = new Scanner(System.in);


		int n = 6;
		char[] charArray = { 'a', 'b', 'c', 'd', 'e', 'f' };
		int[] charfreq = { 5, 9, 12, 13, 16, 45 };


		PriorityQueue<HuffmanNode> q
			= new PriorityQueue<HuffmanNode>(n, new MyComparator());

		for (int i = 0; i < n; i++) {

			HuffmanNode hn = new HuffmanNode();

			hn.c = charArray[i];
			hn.data = charfreq[i];

			hn.left = null;
			hn.right = null;


			q.add(hn);
		}


		HuffmanNode root = null;

		while (q.size() > 1) {


			HuffmanNode x = q.peek();
			q.poll();


			HuffmanNode y = q.peek();
			q.poll();


			HuffmanNode f = new HuffmanNode();

			f.data = x.data + y.data;
			f.c = '-';

			f.left = x;


			f.right = y;


			root = f;


			q.add(f);
		}


		printCode(root, "");
	}
}