Print the longest path from root to leaf in a binary tree
Printing the longest path from the root node to a leaf node in a binary tree using recursion involves finding the path with the maximum number of nodes from the root node to a leaf node, and then printing the values of the nodes on that path.
Program Solution
import java.util.ArrayList;
/*
Java Program
Print the longest path from root to leaf in a binary tree
*/
// Binary Tree node
class TreeNode
{
public int data;
public TreeNode left;
public TreeNode right;
public TreeNode(int data)
{
// Set node value
this.data = data;
this.left = null;
this.right = null;
}
}
public class BinaryTree
{
public TreeNode root;
public BinaryTree()
{
// Set initial tree root to null
this.root = null;
}
// Display given path
public void printPath(ArrayList < Integer > path)
{
int i = 0;
// print path
while (i < path.size())
{
System.out.print(" " + path.get(i));
i++;
}
System.out.print("\n");
}
// Find height of given binary tree
public int treeHeight(TreeNode node)
{
if (node != null)
{
int a = treeHeight(node.left);
int b = treeHeight(node.right);
if (a > b)
{
return a + 1;
}
else
{
return b + 1;
}
}
else
{
return 0;
}
}
// Find all longest path using recursion
public void findLongestPath(TreeNode node,
ArrayList < Integer > path, int height)
{
if (node == null)
{
return;
}
// Add path element
path.add(node.data);
if (node.left == null && node.right == null)
{
if (height == 0)
{
printPath(path);
}
}
else
{
findLongestPath(node.left, path, height - 1);
findLongestPath(node.right, path, height - 1);
}
// Remove last node in path
path.remove(path.size() - 1);
}
// Handles the request of finding longest path in tree
public void longestPaths()
{
// This is use to collect sort path
ArrayList < Integer > path = new ArrayList < Integer > ();
if (this.root == null)
{
// Empty Tree
return;
}
else
{
findLongestPath(this.root, path, treeHeight(this.root)-1);
}
}
public static void main(String[] args)
{
// Create new binary tree
BinaryTree tree = new BinaryTree();
/*
4
/ \
9 7
/ \ \
2 5 12
/ \ / \
6 8 5 18
/ / \
19 3 15
\ \
10 1
-----------------
Constructing binary tree
*/
tree.root = new TreeNode(4);
tree.root.left = new TreeNode(9);
tree.root.left.right = new TreeNode(5);
tree.root.left.right.left = new TreeNode(6);
tree.root.left.right.left.left = new TreeNode(19);
tree.root.left.right.right = new TreeNode(8);
tree.root.left.right.right.left = new TreeNode(3);
tree.root.left.right.right.left.right = new TreeNode(10);
tree.root.left.left = new TreeNode(2);
tree.root.right = new TreeNode(7);
tree.root.right.right = new TreeNode(12);
tree.root.right.right.right = new TreeNode(18);
tree.root.right.right.left = new TreeNode(5);
tree.root.right.right.left.right = new TreeNode(15);
tree.root.right.right.left.right.right = new TreeNode(1);
tree.longestPaths();
}
}
input
4 9 5 8 3 10
4 7 12 5 15 1
// Include header file
#include <iostream>
#include <vector>
using namespace std;
/*
C++ Program
Print the longest path from root to leaf in a binary tree
*/
// Binary Tree node
class TreeNode
{
public: int data;
TreeNode *left;
TreeNode *right;
TreeNode(int data)
{
// Set node value
this->data = data;
this->left = NULL;
this->right = NULL;
}
};
class BinaryTree
{
public: TreeNode *root;
BinaryTree()
{
this->root = NULL;
}
// Display given path
void printPath(vector < int > path)
{
int i = 0;
// print path
while (i < path.size())
{
cout << " " << path.at(i);
i++;
}
cout << "\n";
}
// Find height of given binary tree
int treeHeight(TreeNode *node)
{
if (node != NULL)
{
int a = this->treeHeight(node->left);
int b = this->treeHeight(node->right);
if (a > b)
{
return a + 1;
}
else
{
return b + 1;
}
}
else
{
return 0;
}
}
// Find all longest path using recursion
void findLongestPath(TreeNode *node, vector < int > path, int height)
{
if (node == NULL)
{
return;
}
// Add path element
path.push_back(node->data);
if (node->left == NULL && node->right == NULL)
{
if (height == 0)
{
this->printPath(path);
}
}
else
{
this->findLongestPath(node->left, path, height - 1);
this->findLongestPath(node->right, path, height - 1);
}
// Remove last node in path
path.pop_back();
}
// Handles the request of finding longest path in tree
void longestPaths()
{
// This is use to collect sort path
vector < int > path;
if (this->root == NULL)
{
// Empty Tree
return;
}
else
{
this->findLongestPath(this->root, path, this->treeHeight(this->root) - 1);
}
}
};
int main()
{
// Create new binary tree
BinaryTree *tree = new BinaryTree();
/*
4
/ \
9 7
/ \ \
2 5 12
/ \ / \
6 8 5 18
/ / \
19 3 15
\ \
10 1
-----------------
Constructing binary tree
*/
tree->root = new TreeNode(4);
tree->root->left = new TreeNode(9);
tree->root->left->right = new TreeNode(5);
tree->root->left->right->left = new TreeNode(6);
tree->root->left->right->left->left = new TreeNode(19);
tree->root->left->right->right = new TreeNode(8);
tree->root->left->right->right->left = new TreeNode(3);
tree->root->left->right->right->left->right = new TreeNode(10);
tree->root->left->left = new TreeNode(2);
tree->root->right = new TreeNode(7);
tree->root->right->right = new TreeNode(12);
tree->root->right->right->right = new TreeNode(18);
tree->root->right->right->left = new TreeNode(5);
tree->root->right->right->left->right = new TreeNode(15);
tree->root->right->right->left->right->right = new TreeNode(1);
tree->longestPaths();
return 0;
}
input
4 9 5 8 3 10
4 7 12 5 15 1
// Include namespace system
using System;
using System.Collections.Generic;
/*
Csharp Program
Print the longest path from root to leaf in a binary tree
*/
// Binary Tree node
public class TreeNode
{
public int data;
public TreeNode left;
public TreeNode right;
public TreeNode(int data)
{
// Set node value
this.data = data;
this.left = null;
this.right = null;
}
}
public class BinaryTree
{
public TreeNode root;
public BinaryTree()
{
// Set initial tree root to null
this.root = null;
}
// Display given path
public void printPath(List < int > path)
{
int i = 0;
// print path
while (i < path.Count)
{
Console.Write(" " + path[i]);
i++;
}
Console.Write("\n");
}
// Find height of given binary tree
public int treeHeight(TreeNode node)
{
if (node != null)
{
int a = this.treeHeight(node.left);
int b = this.treeHeight(node.right);
if (a > b)
{
return a + 1;
}
else
{
return b + 1;
}
}
else
{
return 0;
}
}
// Find all longest path using recursion
public void findLongestPath(TreeNode node, List < int > path, int height)
{
if (node == null)
{
return;
}
// Add path element
path.Add(node.data);
if (node.left == null && node.right == null)
{
if (height == 0)
{
this.printPath(path);
}
}
else
{
this.findLongestPath(node.left, path, height - 1);
this.findLongestPath(node.right, path, height - 1);
}
// Remove last node in path
path.RemoveAt(path.Count - 1);
}
// Handles the request of finding longest path in tree
public void longestPaths()
{
// This is use to collect sort path
List < int > path = new List < int > ();
if (this.root == null)
{
// Empty Tree
return;
}
else
{
this.findLongestPath(this.root, path,
this.treeHeight(this.root) - 1);
}
}
public static void Main(String[] args)
{
// Create new binary tree
BinaryTree tree = new BinaryTree();
/*
4
/ \
9 7
/ \ \
2 5 12
/ \ / \
6 8 5 18
/ / \
19 3 15
\ \
10 1
-----------------
Constructing binary tree
*/
tree.root = new TreeNode(4);
tree.root.left = new TreeNode(9);
tree.root.left.right = new TreeNode(5);
tree.root.left.right.left = new TreeNode(6);
tree.root.left.right.left.left = new TreeNode(19);
tree.root.left.right.right = new TreeNode(8);
tree.root.left.right.right.left = new TreeNode(3);
tree.root.left.right.right.left.right = new TreeNode(10);
tree.root.left.left = new TreeNode(2);
tree.root.right = new TreeNode(7);
tree.root.right.right = new TreeNode(12);
tree.root.right.right.right = new TreeNode(18);
tree.root.right.right.left = new TreeNode(5);
tree.root.right.right.left.right = new TreeNode(15);
tree.root.right.right.left.right.right = new TreeNode(1);
tree.longestPaths();
}
}
input
4 9 5 8 3 10
4 7 12 5 15 1
<?php
/*
Php Program
Print the longest path from root to leaf in a binary tree
*/
// Binary Tree node
class TreeNode
{
public $data;
public $left;
public $right;
public function __construct($data)
{
// Set node value
$this->data = $data;
$this->left = NULL;
$this->right = NULL;
}
}
class BinaryTree
{
public $root;
public function __construct()
{
$this->root = NULL;
}
// Display given path
public function printPath($path)
{
$i = 0;
// print path
while ($i < count($path))
{
echo(" ".$path[$i]);
$i++;
}
echo("\n");
}
// Find height of given binary tree
public function treeHeight($node)
{
if ($node != NULL)
{
$a = $this->treeHeight($node->left);
$b = $this->treeHeight($node->right);
if ($a > $b)
{
return $a + 1;
}
else
{
return $b + 1;
}
}
else
{
return 0;
}
}
// Find all longest path using recursion
public function findLongestPath($node, $path, $height)
{
if ($node == NULL)
{
return;
}
// Add path element
$path[] = $node->data;
if ($node->left == NULL && $node->right == NULL)
{
if ($height == 0)
{
$this->printPath($path);
}
}
else
{
$this->findLongestPath($node->left, $path, $height - 1);
$this->findLongestPath($node->right, $path, $height - 1);
}
// Remove last node in path
array_pop($path);
}
// Handles the request of finding longest path in tree
public function longestPaths()
{
// This is use to collect sort path
$path = array();
if ($this->root == NULL)
{
// Empty Tree
return;
}
else
{
$this->findLongestPath($this->root,
$path, $this->treeHeight($this->root) - 1);
}
}
}
function main()
{
// Create new binary tree
$tree = new BinaryTree();
/*
4
/ \
9 7
/ \ \
2 5 12
/ \ / \
6 8 5 18
/ / \
19 3 15
\ \
10 1
-----------------
Constructing binary tree
*/
$tree->root = new TreeNode(4);
$tree->root->left = new TreeNode(9);
$tree->root->left->right = new TreeNode(5);
$tree->root->left->right->left = new TreeNode(6);
$tree->root->left->right->left->left = new TreeNode(19);
$tree->root->left->right->right = new TreeNode(8);
$tree->root->left->right->right->left = new TreeNode(3);
$tree->root->left->right->right->left->right = new TreeNode(10);
$tree->root->left->left = new TreeNode(2);
$tree->root->right = new TreeNode(7);
$tree->root->right->right = new TreeNode(12);
$tree->root->right->right->right = new TreeNode(18);
$tree->root->right->right->left = new TreeNode(5);
$tree->root->right->right->left->right = new TreeNode(15);
$tree->root->right->right->left->right->right = new TreeNode(1);
$tree->longestPaths();
}
main();
input
4 9 5 8 3 10
4 7 12 5 15 1
/*
Node JS Program
Print the longest path from root to leaf in a binary tree
*/
// Binary Tree node
class TreeNode
{
constructor(data)
{
// Set node value
this.data = data;
this.left = null;
this.right = null;
}
}
class BinaryTree
{
constructor()
{
this.root = null;
}
// Display given path
printPath(path)
{
var i = 0;
// print path
while (i < path.length)
{
process.stdout.write(" " + path[i]);
i++;
}
process.stdout.write("\n");
}
// Find height of given binary tree
treeHeight(node)
{
if (node != null)
{
var a = this.treeHeight(node.left);
var b = this.treeHeight(node.right);
if (a > b)
{
return a + 1;
}
else
{
return b + 1;
}
}
else
{
return 0;
}
}
// Find all longest path using recursion
findLongestPath(node, path, height)
{
if (node == null)
{
return;
}
// Add path element
path.push(node.data);
if (node.left == null && node.right == null)
{
if (height == 0)
{
this.printPath(path);
}
}
else
{
this.findLongestPath(node.left, path, height - 1);
this.findLongestPath(node.right, path, height - 1);
}
// Remove last node in path
path.pop();
}
// Handles the request of finding longest path in tree
longestPaths()
{
// This is use to collect sort path
var path = [];
if (this.root == null)
{
// Empty Tree
return;
}
else
{
this.findLongestPath(this.root,
path, this.treeHeight(this.root) - 1);
}
}
}
function main()
{
// Create new binary tree
var tree = new BinaryTree();
/*
4
/ \
9 7
/ \ \
2 5 12
/ \ / \
6 8 5 18
/ / \
19 3 15
\ \
10 1
-----------------
Constructing binary tree
*/
tree.root = new TreeNode(4);
tree.root.left = new TreeNode(9);
tree.root.left.right = new TreeNode(5);
tree.root.left.right.left = new TreeNode(6);
tree.root.left.right.left.left = new TreeNode(19);
tree.root.left.right.right = new TreeNode(8);
tree.root.left.right.right.left = new TreeNode(3);
tree.root.left.right.right.left.right = new TreeNode(10);
tree.root.left.left = new TreeNode(2);
tree.root.right = new TreeNode(7);
tree.root.right.right = new TreeNode(12);
tree.root.right.right.right = new TreeNode(18);
tree.root.right.right.left = new TreeNode(5);
tree.root.right.right.left.right = new TreeNode(15);
tree.root.right.right.left.right.right = new TreeNode(1);
tree.longestPaths();
}
main();
input
4 9 5 8 3 10
4 7 12 5 15 1
# Python 3 Program
# Print the longest path from root to leaf in a binary tree
# Binary Tree node
class TreeNode :
def __init__(self, data) :
# Set node value
self.data = data
self.left = None
self.right = None
class BinaryTree :
def __init__(self) :
self.root = None
# Display given path
def printPath(self, path) :
i = 0
# print path
while (i < len(path)) :
print(" ", path[i], end = "")
i += 1
print(end = "\n")
# Find height of given binary tree
def treeHeight(self, node) :
if (node != None) :
a = self.treeHeight(node.left)
b = self.treeHeight(node.right)
if (a > b) :
return a + 1
else :
return b + 1
else :
return 0
# Find all longest path using recursion
def findLongestPath(self, node, path, height) :
if (node == None) :
return
# Add path element
path.append(node.data)
if (node.left == None and node.right == None) :
if (height == 0) :
self.printPath(path)
else :
self.findLongestPath(node.left, path, height - 1)
self.findLongestPath(node.right, path, height - 1)
# Remove last node in path
del path[len(path) - 1]
# Handles the request of finding longest path in tree
def longestPaths(self) :
# This is use to collect sort path
path = []
if (self.root == None) :
# Empty Tree
return
else :
self.findLongestPath(self.root,
path, self.treeHeight(self.root) - 1)
def main() :
# Create new binary tree
tree = BinaryTree()
# 4
# / \
# 9 7
# / \ \
# 2 5 12
# / \ / \
# 6 8 5 18
# / / \
# 19 3 15
# \ \
# 10 1
# -----------------
# Constructing binary tree
tree.root = TreeNode(4)
tree.root.left = TreeNode(9)
tree.root.left.right = TreeNode(5)
tree.root.left.right.left = TreeNode(6)
tree.root.left.right.left.left = TreeNode(19)
tree.root.left.right.right = TreeNode(8)
tree.root.left.right.right.left = TreeNode(3)
tree.root.left.right.right.left.right = TreeNode(10)
tree.root.left.left = TreeNode(2)
tree.root.right = TreeNode(7)
tree.root.right.right = TreeNode(12)
tree.root.right.right.right = TreeNode(18)
tree.root.right.right.left = TreeNode(5)
tree.root.right.right.left.right = TreeNode(15)
tree.root.right.right.left.right.right = TreeNode(1)
tree.longestPaths()
if __name__ == "__main__": main()
input
4 9 5 8 3 10
4 7 12 5 15 1
# Ruby Program
# Print the longest path from root to leaf in a binary tree
# Binary Tree node
class TreeNode
# Define the accessor and reader of class TreeNode
attr_reader :data, :left, :right
attr_accessor :data, :left, :right
def initialize(data)
# Set node value
self.data = data
self.left = nil
self.right = nil
end
end
class BinaryTree
# Define the accessor and reader of class BinaryTree
attr_reader :root
attr_accessor :root
def initialize()
self.root = nil
end
# Display given path
def printPath(path)
i = 0
# print path
while (i < path.length)
print(" ", path[i])
i += 1
end
print("\n")
end
# Find height of given binary tree
def treeHeight(node)
if (node != nil)
a = self.treeHeight(node.left)
b = self.treeHeight(node.right)
if (a > b)
return a + 1
else
return b + 1
end
else
return 0
end
end
# Find all longest path using recursion
def findLongestPath(node, path, height)
if (node == nil)
return
end
# Add path element
path.push(node.data)
if (node.left == nil && node.right == nil)
if (height == 0)
self.printPath(path)
end
else
self.findLongestPath(node.left, path, height - 1)
self.findLongestPath(node.right, path, height - 1)
end
# Remove last node in path
path.delete_at(path.length - 1)
end
# Handles the request of finding longest path in tree
def longestPaths()
# This is use to collect sort path
path = []
if (self.root == nil)
# Empty Tree
return
else
self.findLongestPath(self.root,
path, self.treeHeight(self.root) - 1)
end
end
end
def main()
# Create new binary tree
tree = BinaryTree.new()
# 4
# / \
# 9 7
# / \ \
# 2 5 12
# / \ / \
# 6 8 5 18
# / / \
# 19 3 15
# \ \
# 10 1
# -----------------
# Constructing binary tree
tree.root = TreeNode.new(4)
tree.root.left = TreeNode.new(9)
tree.root.left.right = TreeNode.new(5)
tree.root.left.right.left = TreeNode.new(6)
tree.root.left.right.left.left = TreeNode.new(19)
tree.root.left.right.right = TreeNode.new(8)
tree.root.left.right.right.left = TreeNode.new(3)
tree.root.left.right.right.left.right = TreeNode.new(10)
tree.root.left.left = TreeNode.new(2)
tree.root.right = TreeNode.new(7)
tree.root.right.right = TreeNode.new(12)
tree.root.right.right.right = TreeNode.new(18)
tree.root.right.right.left = TreeNode.new(5)
tree.root.right.right.left.right = TreeNode.new(15)
tree.root.right.right.left.right.right = TreeNode.new(1)
tree.longestPaths()
end
main()
input
4 9 5 8 3 10
4 7 12 5 15 1
import scala.collection.mutable._;
/*
Scala Program
Print the longest path from root to leaf in a binary tree
*/
// Binary Tree node
class TreeNode(var data: Int,
var left: TreeNode,
var right: TreeNode)
{
def this(data: Int)
{
// Set node value
this(data,null,null);
}
}
class BinaryTree(var root: TreeNode)
{
def this()
{
this(null);
}
// Display given path
def printPath(path: ArrayBuffer[Int]): Unit = {
var i: Int = 0;
// print path
while (i < path.size)
{
print(" " + path(i));
i += 1;
}
print("\n");
}
// Find height of given binary tree
def treeHeight(node: TreeNode): Int = {
if (node != null)
{
var a: Int = treeHeight(node.left);
var b: Int = treeHeight(node.right);
if (a > b)
{
return a + 1;
}
else
{
return b + 1;
}
}
else
{
return 0;
}
}
// Find all longest path using recursion
def findLongestPath(node: TreeNode, path:
ArrayBuffer[Int], height: Int): Unit = {
if (node == null)
{
return;
}
// Add path element
path += node.data;
if (node.left == null && node.right == null)
{
if (height == 0)
{
printPath(path);
}
}
else
{
findLongestPath(node.left, path, height - 1);
findLongestPath(node.right, path, height - 1);
}
// Remove last node in path
path.remove(path.size - 1);
}
// Handles the request of finding longest path in tree
def longestPaths(): Unit = {
// This is use to collect sort path
var path: ArrayBuffer[Int] = new ArrayBuffer[Int]();
if (this.root == null)
{
// Empty Tree
return;
}
else
{
findLongestPath(this.root, path, treeHeight(this.root) - 1);
}
}
}
object Main
{
def main(args: Array[String]): Unit = {
// Create new binary tree
var tree: BinaryTree = new BinaryTree();
/*
4
/ \
9 7
/ \ \
2 5 12
/ \ / \
6 8 5 18
/ / \
19 3 15
\ \
10 1
-----------------
Constructing binary tree
*/
tree.root = new TreeNode(4);
tree.root.left = new TreeNode(9);
tree.root.left.right = new TreeNode(5);
tree.root.left.right.left = new TreeNode(6);
tree.root.left.right.left.left = new TreeNode(19);
tree.root.left.right.right = new TreeNode(8);
tree.root.left.right.right.left = new TreeNode(3);
tree.root.left.right.right.left.right = new TreeNode(10);
tree.root.left.left = new TreeNode(2);
tree.root.right = new TreeNode(7);
tree.root.right.right = new TreeNode(12);
tree.root.right.right.right = new TreeNode(18);
tree.root.right.right.left = new TreeNode(5);
tree.root.right.right.left.right = new TreeNode(15);
tree.root.right.right.left.right.right = new TreeNode(1);
tree.longestPaths();
}
}
input
4 9 5 8 3 10
4 7 12 5 15 1
import Foundation;
/*
Swift 4 Program
Print the longest path from root to leaf in a binary tree
*/
// Binary Tree node
class TreeNode
{
var data: Int;
var left: TreeNode? ;
var right: TreeNode? ;
init(_ data: Int)
{
// Set node value
self.data = data;
self.left = nil;
self.right = nil;
}
}
class BinaryTree
{
var root: TreeNode? ;
init()
{
self.root = nil;
}
// Display given path
func printPath(_ path: [Int])
{
var i = 0;
// print path
while (i < path.count)
{
print(" ", path[i], terminator: "");
i += 1;
}
print(terminator: "\n");
}
// Find height of given binary tree
func treeHeight(_ node: TreeNode? ) -> Int
{
if (node != nil)
{
let a = self.treeHeight(node!.left);
let b = self.treeHeight(node!.right);
if (a > b)
{
return a + 1;
}
else
{
return b + 1;
}
}
else
{
return 0;
}
}
// Find all longest path using recursion
func findLongestPath(_ node: TreeNode? , _ path : inout[Int], _ height: Int)
{
if (node == nil)
{
return;
}
// Add path element
path.append(node!.data);
if (node!.left == nil && node!.right == nil)
{
if (height == 0)
{
self.printPath(path);
}
}
else
{
self.findLongestPath(node!.left, &path, height - 1);
self.findLongestPath(node!.right, &path, height - 1);
}
// Remove last node in path
path.removeLast();
}
// Handles the request of finding longest path in tree
func longestPaths()
{
// This is use to collect sort path
var path = [Int]();
if (self.root == nil)
{
// Empty Tree
return;
}
else
{
self.findLongestPath(self.root, &path,
self.treeHeight(self.root) - 1);
}
}
}
func main()
{
// Create new binary tree
let tree = BinaryTree();
/*
4
/ \
9 7
/ \ \
2 5 12
/ \ / \
6 8 5 18
/ / \
19 3 15
\ \
10 1
-----------------
Constructing binary tree
*/
tree.root = TreeNode(4);
tree.root!.left = TreeNode(9);
tree.root!.left!.right = TreeNode(5);
tree.root!.left!.right!.left = TreeNode(6);
tree.root!.left!.right!.left!.left = TreeNode(19);
tree.root!.left!.right!.right = TreeNode(8);
tree.root!.left!.right!.right!.left = TreeNode(3);
tree.root!.left!.right!.right!.left!.right = TreeNode(10);
tree.root!.left!.left = TreeNode(2);
tree.root!.right = TreeNode(7);
tree.root!.right!.right = TreeNode(12);
tree.root!.right!.right!.right = TreeNode(18);
tree.root!.right!.right!.left = TreeNode(5);
tree.root!.right!.right!.left!.right = TreeNode(15);
tree.root!.right!.right!.left!.right!.right = TreeNode(1);
tree.longestPaths();
}
main();
input
4 9 5 8 3 10
4 7 12 5 15 1
/*
Kotlin Program
Print the longest path from root to leaf in a binary tree
*/
// Binary Tree node
class TreeNode
{
var data: Int;
var left: TreeNode ? ;
var right: TreeNode ? ;
constructor(data: Int)
{
// Set node value
this.data = data;
this.left = null;
this.right = null;
}
}
class BinaryTree
{
var root: TreeNode ? ;
constructor()
{
this.root = null;
}
// Display given path
fun printPath(path: MutableList<Int> ): Unit
{
var i: Int = 0;
// print path
while (i < path.size)
{
print(" " + path[i]);
i += 1;
}
print("\n");
}
// Find height of given binary tree
fun treeHeight(node: TreeNode ? ): Int
{
if (node != null)
{
val a: Int = this.treeHeight(node.left);
val b: Int = this.treeHeight(node.right);
if (a > b)
{
return a + 1;
}
else
{
return b + 1;
}
}
else
{
return 0;
}
}
// Find all longest path using recursion
fun findLongestPath(node: TreeNode ? ,
path : MutableList<Int> , height : Int): Unit
{
if (node == null)
{
return;
}
// Add path element
path.add(node.data);
if (node.left == null && node.right == null)
{
if (height == 0)
{
this.printPath(path);
}
}
else
{
this.findLongestPath(node.left, path, height - 1);
this.findLongestPath(node.right, path, height - 1);
}
// Remove last node in path
path.removeAt(path.size - 1);
}
// Handles the request of finding longest path in tree
fun longestPaths(): Unit
{
// This is use to collect sort path
var path = mutableListOf<Int>();
if (this.root == null)
{
// Empty Tree
return;
}
else
{
this.findLongestPath(this.root,
path, this.treeHeight(this.root) - 1);
}
}
}
fun main(args: Array < String > ): Unit
{
// Create new binary tree
val tree: BinaryTree = BinaryTree();
/*
4
/ \
9 7
/ \ \
2 5 12
/ \ / \
6 8 5 18
/ / \
19 3 15
\ \
10 1
-----------------
Constructing binary tree
*/
tree.root = TreeNode(4);
tree.root?.left = TreeNode(9);
tree.root?.left?.right = TreeNode(5);
tree.root?.left?.right?.left = TreeNode(6);
tree.root?.left?.right?.left?.left = TreeNode(19);
tree.root?.left?.right?.right = TreeNode(8);
tree.root?.left?.right?.right?.left = TreeNode(3);
tree.root?.left?.right?.right?.left?.right = TreeNode(10);
tree.root?.left?.left = TreeNode(2);
tree.root?.right = TreeNode(7);
tree.root?.right?.right = TreeNode(12);
tree.root?.right?.right?.right = TreeNode(18);
tree.root?.right?.right?.left = TreeNode(5);
tree.root?.right?.right?.left?.right = TreeNode(15);
tree.root?.right?.right?.left?.right?.right = TreeNode(1);
tree.longestPaths();
}
input
4 9 5 8 3 10
4 7 12 5 15 1
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