Question:Given the root pointer to a binary tree, find the number of full nodes.

Input:Sample Tree (Pointer to node 1 is given). Find the number of full nodes.

Output:Number of full nodes = 3

*According to the definition, the set of all nodes with both left and right child are called as full nodes.*

In the above example, we have the nodes – 1. 2, 3 as full nodes.

We can perform a level order traversal and count the number of nodes, who have their right child and left child as not null. Return the count in the end.

#include<stdio.h> #include<malloc.h> struct binaryTreeNode{ int data; struct binaryTreeNode * left; struct binaryTreeNode * right; }; int numberOfFullNodes(struct binaryTreeNode * root) { // Level order traversal struct binaryTreeNode * temp = NULL; struct queue * Q = NULL; // Maintain a count int count = 0; if(root == NULL) return 0; Q = enQueue(Q, root); while(!isQueueEmpty(Q)) { temp = Q -> front -> data; // Now check if the node is a leaf node if(temp -> left != NULL && temp -> right != NULL) { // This means a full node count++; } Q = deQueue(Q); if(temp -> left) Q = enQueue(Q, temp -> left); if(temp -> right) Q = enQueue(Q, temp -> right); } // Delete the queue free(Q); // Now return the count return count; }

*Time Complexity:-* O(n)

*Space Complexity:-* O(n)

**Ideone link for the sample program:-** http://ideone.com/0C5baa