Lecture 294:- Student Challenge Count Leaf Nodes Of Binary Tree

To count the number of leaf nodes in a binary tree, we can perform a simple depth-first traversal (postorder) and increment a counter for each leaf node encountered. Here's the C++ implementation to count the leaf nodes of a binary tree:

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#include <iostream> using namespace std; struct TreeNode {    int val;    TreeNode* left;    TreeNode* right;    TreeNode(int data) : val(data), left(nullptr), right(nullptr) {} }; int countLeafNodes(TreeNode* root) {    if (root == nullptr)        return 0;    if (root->left == nullptr && root->right == nullptr)        return 1;    return countLeafNodes(root->left) + countLeafNodes(root->right); } int main() {    // Create a binary tree:    //        1    //       / \    //      2   3    //     / \    //    4   5    TreeNode* root = new TreeNode(1);    root->left = new TreeNode(2);    root->right = new TreeNode(3);    root->left->left = new TreeNode(4);    root->left->right = new TreeNode(5);    int leafNodeCount = countLeafNodes(root);    cout << "Number of Leaf Nodes in the Binary Tree: " << leafNodeCount << endl;    // Remember to free the allocated memory after use to avoid memory leaks.    delete root->left->left;    delete root->left->right;    delete root->left;    delete root->right;    delete root;    return 0; }

Output:

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Number of Leaf Nodes in the Binary Tree: 3

In this example, we calculate the number of leaf nodes in the binary tree, which is 3. Leaf nodes are nodes with no children (both left and right children are nullptr).