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Find the node with maximum value in a Binary Search Tree
• Difficulty Level : Easy
• Last Updated : 10 Jul, 2019

Given a Binary Search Tree, the task is to find the node with the maximum value in a BST. For the above tree, we start with 20, then we move right 22, we keep on moving to right until we see NULL. Since right of 22 is NULL, 22 is the node with maximum value.

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach: This is quite simple. Just traverse the node from root to right recursively until right is NULL. The node whose right is NULL is the node with maximum value.

## C++

 `#include ``using` `namespace` `std;`` ` `/* A binary tree node has data, pointer to left child  ``   ``and a pointer to right child */``struct` `node {``    ``int` `data;``    ``struct` `node* left;``    ``struct` `node* right;``};`` ` `// Function to create a new node``struct` `node* newNode(``int` `data)``{``    ``struct` `node* node = (``struct` `node*)``        ``malloc``(``sizeof``(``struct` `node));``    ``node->data = data;``    ``node->left = NULL;``    ``node->right = NULL;`` ` `    ``return` `(node);``}`` ` `// Function to insert a new node in BST``struct` `node* insert(``struct` `node* node, ``int` `data)``{``    ``/* 1. If the tree is empty, return a new,      ``      ``single node */``    ``if` `(node == NULL)``        ``return` `(newNode(data));``    ``else` `{``        ``/* 2. Otherwise, recur down the tree */``        ``if` `(data <= node->data)``            ``node->left = insert(node->left, data);``        ``else``            ``node->right = insert(node->right, data);`` ` `        ``/* return the (unchanged) node pointer */``        ``return` `node;``    ``}``}`` ` `// Function to find the node with maximum value``// i.e. rightmost leaf node``int` `maxValue(``struct` `node* node)``{   ``    ``/* loop down to find the rightmost leaf */``    ``struct` `node* current = node;``    ``while` `(current->right != NULL) ``        ``current = current->right;``     ` `    ``return` `(current->data);``}`` ` `// Driver code``int` `main()``{``    ``struct` `node* root = NULL;``    ``root = insert(root, 4);``    ``insert(root, 2);``    ``insert(root, 1);``    ``insert(root, 3);``    ``insert(root, 6);``    ``insert(root, 5);`` ` `    ``cout << ``"Maximum value in BST is "` `<< maxValue(root);`` ` `    ``return` `0;``}`

## Java

 `// Java implementation to find the sum of last``// 'n' nodes of the Linked List``import` `java.util.*;`` ` `class` `GFG``{`` ` ` ` `/* A binary tree node has data, pointer to left child ``and a pointer to right child */``static` `class` `node``{``    ``int` `data;``    ``node left;``    ``node right;``};`` ` `// Function to create a new node``static` `node newNode(``int` `data)``{``    ``node node = ``new` `node();``    ``node.data = data;``    ``node.left = ``null``;``    ``node.right = ``null``;`` ` `    ``return` `(node);``}`` ` `// Function to insert a new node in BST``static` `node insert(node node, ``int` `data)``{``    ``/* 1. If the tree is empty, return a new,     ``    ``single node */``    ``if` `(node == ``null``)``        ``return` `(newNode(data));``    ``else` `    ``{``        ``/* 2. Otherwise, recur down the tree */``        ``if` `(data <= node.data)``            ``node.left = insert(node.left, data);``        ``else``            ``node.right = insert(node.right, data);`` ` `        ``/* return the (unchanged) node pointer */``        ``return` `node;``    ``}``}`` ` `// Function to find the node with maximum value``// i.e. rightmost leaf node``static` `int` `maxValue(node node)``{ ``    ``/* loop down to find the rightmost leaf */``    ``node current = node;``    ``while` `(current.right != ``null``) ``        ``current = current.right;``     ` `    ``return` `(current.data);``}`` ` `// Driver code``public` `static` `void` `main(String[] args) ``{``    ``node root = ``null``;``    ``root = insert(root, ``4``);``    ``insert(root, ``2``);``    ``insert(root, ``1``);``    ``insert(root, ``3``);``    ``insert(root, ``6``);``    ``insert(root, ``5``);`` ` `    ``System.out.println(``"Maximum value in BST is "` `+ maxValue(root));``}``}`` ` `/* This code is contributed by PrinciRaj1992 */`

## Python3

 `import` `sys``import` `math`` ` `# A binary tree node has data, pointer to left child ``# and a pointer to right child ``class` `Node:``    ``def` `__init__(``self``,data):``        ``self``.data ``=` `data``        ``self``.left ``=` `None``        ``self``.right ``=` `None`` ` `# Function to insert a new node in BST``def` `insert(root, data):`` ` `    ``# 1. If the tree is empty, return a new,     ``    ``# single node``    ``if` `not` `root:``        ``return` `Node(data)`` ` `    ``# 2. Otherwise, recur down the tree``    ``if` `data < root.data:``        ``root.left ``=` `insert(root.left, data)``    ``if` `data > root.data:``        ``root.right ``=` `insert(root.right, data)``     ` `    ``# return the (unchanged) node pointer``    ``return` `root`` ` `# Function to find the node with maximum value ``# i.e. rightmost leaf node ``def` `maxValue(root):``    ``current ``=` `root``     ` `    ``#loop down to find the rightmost leaf``    ``while``(current.right):``        ``current ``=` `current.right``    ``return` `current.data`` ` `# Driver code ``if` `__name__``=``=``'__main__'``:``    ``root``=``None``    ``root ``=` `insert(root,``2``)``    ``root ``=` `insert(root,``1``)``    ``root ``=` `insert(root,``3``)``    ``root ``=` `insert(root,``6``)``    ``root ``=` `insert(root,``5``)``    ``print``(``"Maximum value in BST is {}"``.``format``(maxValue(root)))`` ` `# This code is contributed by Vikash Kumar 37`

## C#

 `// C# implementation to find the sum of last ``// 'n' nodes of the Linked List ``using` `System;`` ` `class` `GFG ``{ `` ` ` ` `/* A binary tree node has data, pointer to left child ``and a pointer to right child */``public` `class` `node ``{ ``    ``public` `int` `data; ``    ``public` `node left; ``    ``public` `node right; ``}; `` ` `// Function to create a new node ``static` `node newNode(``int` `data) ``{ ``    ``node node = ``new` `node(); ``    ``node.data = data; ``    ``node.left = ``null``; ``    ``node.right = ``null``; `` ` `    ``return` `(node); ``} `` ` `// Function to insert a new node in BST ``static` `node insert(node node, ``int` `data) ``{ ``    ``/* 1. If the tree is empty, return a new, ``    ``single node */``    ``if` `(node == ``null``) ``        ``return` `(newNode(data)); ``    ``else``    ``{ ``        ``/* 2. Otherwise, recur down the tree */``        ``if` `(data <= node.data) ``            ``node.left = insert(node.left, data); ``        ``else``            ``node.right = insert(node.right, data); `` ` `        ``/* return the (unchanged) node pointer */``        ``return` `node; ``    ``} ``} `` ` `// Function to find the node with maximum value ``// i.e. rightmost leaf node ``static` `int` `maxValue(node node) ``{ ``    ``/* loop down to find the rightmost leaf */``    ``node current = node; ``    ``while` `(current.right != ``null``) ``        ``current = current.right; ``     ` `    ``return` `(current.data); ``} `` ` `// Driver code ``public` `static` `void` `Main(String[] args) ``{ ``    ``node root = ``null``; ``    ``root = insert(root, 4); ``    ``insert(root, 2); ``    ``insert(root, 1); ``    ``insert(root, 3); ``    ``insert(root, 6); ``    ``insert(root, 5); `` ` `    ``Console.WriteLine(``"Maximum value in BST is "` `+ maxValue(root)); ``} ``} `` ` `// This code is contributed by Rajput-Ji`
Output:
```Maximum value in BST is 6
```

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