add complete tree nodes in java

Author: 0ChanAk

JAVA/Count_complete_tree_nodes.java

@@ -0,0 +1,100 @@
+/*
+Given the root of a Complete Binary Tree consisting of N nodes, the task is to find the total number of nodes in the given Binary Tree.
+*/
+
+// Java program for the above approach
+import java.util.*;
+
+class GFG{
+
+// Structure of a Tree Node
+static class node {
+
+	int data;
+	node left;
+	node right;
+};
+
+
+// Function to get the left height of
+// the binary tree
+static int left_height(node node)
+{
+	int ht = 0;
+	while (node!=null) {
+		ht++;
+		node = node.left;
+	}
+
+	// Return the left height obtained
+	return ht;
+}
+
+// Function to get the right height
+// of the binary tree
+static int right_height(node node)
+{
+	int ht = 0;
+	while (node!=null) {
+		ht++;
+		node = node.right;
+	}
+
+	// Return the right height obtained
+	return ht;
+}
+
+// Function to get the count of nodes
+// in complete binary tree
+static int TotalNodes(node root)
+{
+
+	// Base Case
+	if (root == null)
+		return 0;
+
+	// Find the left height and the
+	// right heights
+	int lh = left_height(root);
+	int rh = right_height(root);
+
+	// If left and right heights are
+	// equal return 2^height(1<<height) -1
+	if (lh == rh)
+		return (1 << lh) - 1;
+
+	// Otherwise, recursive call
+	return 1 + TotalNodes(root.left)
+		+ TotalNodes(root.right);
+}
+
+// Helper function to allocate a new node
+// with the given data
+static node newNode(int data)
+{
+	node Node = new node();
+	Node.data = data;
+	Node.left = null;
+	Node.right = null;
+	return (Node);
+}
+
+// Driver Code
+  public static void main(String[] args)
+  {
+      node root = newNode(1);
+      root.left = newNode(2);
+      root.right = newNode(3);
+      root.left.left = newNode(4);
+      root.left.right = newNode(5);
+      root.right.left = newNode(9);
+      root.right.right = newNode(8);
+      root.left.left.left = newNode(6);
+      root.left.left.right = newNode(7);
+
+      System.out.print(TotalNodes(root));
+
+  }
+}
+
+// This code is contributed by shikhasingrajput