Added Huffman encoding algorithm in java

src/main/java/com/thealgorithms/greedyalgorithms/Huffman.java

@@ -0,0 +1,77 @@
+// Huffman Coding in Java
+
+import java.util.PriorityQueue;
+import java.util.Comparator;
+
+class HuffmanNode {
+    int item;
+    char c;
+    HuffmanNode left;
+    HuffmanNode right;
+}
+
+// For comparing the nodes
+class ImplementComparator implements Comparator<HuffmanNode> {
+    public int compare(HuffmanNode x, HuffmanNode y) {
+        return x.item - y.item;
+    }
+}
+
+// IMplementing the huffman algorithm
+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) {
+
+        int n = 4;
+        char[] charArray = { 'A', 'B', 'C', 'D' };
+        int[] charfreq = { 5, 1, 6, 3 };
+
+        PriorityQueue<HuffmanNode> q = new PriorityQueue<HuffmanNode>(n, new ImplementComparator());
+
+        for (int i = 0; i < n; i++) {
+            HuffmanNode hn = new HuffmanNode();
+
+            hn.c = charArray[i];
+            hn.item = 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.item = x.item + y.item;
+            f.c = '-';
+            f.left = x;
+            f.right = y;
+            root = f;
+
+            q.add(f);
+        }
+        System.out.println(" Char | Huffman code ");
+        System.out.println("--------------------");
+        printCode(root, "");
+    }
+}