Print all leaf nodes of a Binary Tree from left to right
Given a binary tree, we need to write a program to print all leaf nodes of the given binary tree from left to right. That is, the nodes should be printed in the order they appear from left to right in the given tree.
For Example,
For the above binary tree, output will be as shown below:
4 6 7 9 10
The idea to do this is similar to DFS algorithm. Below is step by step algorithm to do this:
- Check if given node is null. If null, then return from the function.
- Check if it is a leaf node. If the node is a leaf node, then print its data.
- If in above step, node is not a leaf node then check if left and right childs of node exists. If yes then call function for left and right childs of the node recursively.
Below is C++ implementation of above approach.
/* C++ program to print leaf nodes from left to right */#include <iostream> using namespace std; // A Binary Tree Node struct Node { int data; struct Node *left, *right; }; // function to print leaf // nodes from left to right void printLeafNodes(Node *root) { // if node is null, return if (!root) return; // if node is leaf node, print its data if (!root->left && !root->right) { cout << root->data << " "; return; } // if left child exists, check for leaf // recursively if (root->left) printLeafNodes(root->left); // if right child exists, check for leaf // recursively if (root->right) printLeafNodes(root->right); } // Utility function to create a new tree node Node* newNode(int data) { Node *temp = new Node; temp->data = data; temp->left = temp->right = NULL; return temp; } // Driver program to test above functions int main() { // Let us create binary tree shown in // above diagram Node *root = newNode(1); root->left = newNode(2); root->right = newNode(3); root->left->left = newNode(4); root->right->left = newNode(5); root->right->right = newNode(8); root->right->left->left = newNode(6); root->right->left->right = newNode(7); root->right->right->left = newNode(9); root->right->right->right = newNode(10); // print leaf nodes of the given tree printLeafNodes(root); return 0; } |
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Output:
4 6 7 9 10
Time Complexity: O( n ) , where n is number of nodes in the binary tree.
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