Given Preorder traversal of a Binary Search Tree. Then the task is print leaf nodes of the Binary Search Tree from the given preorder.
Examples :
Input : preorder[] = {890, 325, 290, 530, 965};
Output : 290 530 965
Tree represented is,
890
/ \
325 965
/ \
290 530
Input : preorder[] = { 3, 2, 4 };
Output : 2 4
In this post, a simple recursive solution is discussed. The idea is to use two min and max variables and taking i (index in input array), the index for given preorder array, and recursively creating root node and correspondingly checking if left and right are existing or not. This method return boolean variable, and if both left and right are false it simply means that left and right are null hence it must be a leaf node so print it right there and return back true as root at that index existed.
C++
// Recursive C++ program to find leaf // nodes from given preorder traversal #include<bits/stdc++.h> using namespace std; // Print the leaf node from // the given preorder of BST. bool isLeaf(int pre[], int &i, int n, int min, int max) { if (i >= n) return false; if (pre[i] > min && pre[i] < max) { i++; bool left = isLeaf(pre, i, n, min, pre[i-1]); bool right = isLeaf(pre, i, n, pre[i-1], max); if (!left && !right) cout << pre[i-1] << " "; return true; } return false; } void printLeaves(int preorder[], int n) { int i = 0; isLeaf(preorder, i, n, INT_MIN, INT_MAX); } // Driver code int main() { int preorder[] = { 890, 325, 290, 530, 965 }; int n = sizeof(preorder)/sizeof(preorder[0]); printLeaves(preorder, n); return 0; } |
chevron_right
filter_none
Java
// Recursive Java program to find leaf // nodes from given preorder traversal class GFG { static int i = 0; // Print the leaf node from // the given preorder of BST. static boolean isLeaf(int pre[], int n, int min, int max) { if (i >= n) { return false; } if (pre[i] > min && pre[i] < max) { i++; boolean left = isLeaf(pre, n, min, pre[i - 1]); boolean right = isLeaf(pre, n, pre[i - 1], max); if (!left && !right) { System.out.print(pre[i - 1] + " "); } return true; } return false; } static void printLeaves(int preorder[], int n) { isLeaf(preorder, n, Integer.MIN_VALUE, Integer.MAX_VALUE); } // Driver code public static void main(String[] args) { int preorder[] = {890, 325, 290, 530, 965}; int n = preorder.length; printLeaves(preorder, n); } } // This code contributed by Rajput-Ji |
chevron_right
filter_none
Python3
# Recursive Python program to find leaf # nodes from given preorder traversal # Print the leaf node from # the given preorder of BST. def isLeaf(pre, i, n, Min, Max): if i[0] >= n: return False if pre[i[0]] > Min and pre[i[0]] < Max: i[0] += 1 left = isLeaf(pre, i, n, Min, pre[i[0] - 1]) right = isLeaf(pre, i, n, pre[i[0] - 1], Max) if left == False and right == False: print(pre[i[0] - 1], end = " ") return True return False def printLeaves(preorder, n): i = [0] INT_MIN, INT_MAX = -999999999999, 999999999999 isLeaf(preorder, i, n, INT_MIN, INT_MAX) # Driver code if __name__ == '__main__': preorder = [890, 325, 290, 530, 965] n = len(preorder) printLeaves(preorder, n) # This code is contributed by PranchalK |
chevron_right
filter_none
C#
// Recursive C# program to find leaf // nodes from given preorder traversal using System; class GFG { static int i = 0; // Print the leaf node from // the given preorder of BST. static bool isLeaf(int []pre, int n, int min, int max) { if (i >= n) { return false; } if (pre[i] > min && pre[i] < max) { i++; bool left = isLeaf(pre, n, min, pre[i - 1]); bool right = isLeaf(pre, n, pre[i - 1], max); if (!left && !right) { Console.Write(pre[i - 1] + " "); } return true; } return false; } static void printLeaves(int []preorder, int n) { isLeaf(preorder, n, int.MinValue, int.MaxValue); } // Driver code public static void Main(String[] args) { int []preorder = {890, 325, 290, 530, 965}; int n = preorder.Length; printLeaves(preorder, n); } } // This code is contributed by princiraj1992 |
chevron_right
filter_none
PHP
<?php // Recursive PHP program to // find leaf nodes from given // preorder traversal // Print the leaf node from // the given preorder of BST. function isLeaf($pre, &$i, $n, $min, $max) { if ($i >= $n) return false; if ($pre[$i] > $min && $pre[$i] < $max) { $i++; $left = isLeaf($pre, $i, $n, $min, $pre[$i - 1]); $right = isLeaf($pre, $i, $n, $pre[$i - 1], $max); if (!$left && !$right) echo $pre[$i - 1] , " "; return true; } return false; } function printLeaves($preorder, $n) { $i = 0; isLeaf($preorder, $i, $n, PHP_INT_MIN, PHP_INT_MAX); } // Driver code $preorder = array (890, 325, 290, 530, 965 ); $n = sizeof($preorder); printLeaves($preorder, $n); // This code is contributed by ajit ?> |
chevron_right
filter_none
Output :
290 530 965
Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the DSA Self Paced Course at a student-friendly price and become industry ready.
Recommended Posts:
- Construct Full Binary Tree using its Preorder traversal and Preorder traversal of its mirror tree
- Check if a binary tree is subtree of another binary tree using preorder traversal : Iterative
- Create Balanced Binary Tree using its Leaf Nodes without using extra space
- Print the longest leaf to leaf path in a Binary tree
- Construct XOR tree by Given leaf nodes of Perfect Binary Tree
- Check if a given array can represent Preorder Traversal of Binary Search Tree
- Preorder Traversal of N-ary Tree Without Recursion
- Complexity of different operations in Binary tree, Binary Search Tree and AVL tree
- Print leaf nodes in binary tree from left to right using one stack
- Find the node with minimum value in a Binary Search Tree using recursion
- Find the node with maximum value in a Binary Search Tree using recursion
- Binary Tree to Binary Search Tree Conversion using STL set
- Remove all leaf nodes from a Generic Tree or N-ary Tree
- Program to count leaf nodes in a binary tree
- Find height of a special binary tree whose leaf nodes are connected
- Iterative program to count leaf nodes in a Binary Tree
- Sum of all leaf nodes of binary tree
- Print all leaf nodes of a Binary Tree from left to right
- Pairwise Swap leaf nodes in a binary tree
- Count Non-Leaf nodes in a Binary Tree
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.
