# Deepest right leaf node in a binary tree | Iterative approach

Given a Binary Tree, find the deepest leaf node that is right child of its parent. For example, consider the following tree. The deepest right leaf node is the node with value 10.

Examples:

```Input :
1
/   \
2     3
\   /  \
4 5    6
\    \
7    8
/      \
9        10

Output : 10
```

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

The idea is similar to Method 2 of level order traversal

Traverse the tree level by level and while pushing right child to queue, check if it is leaf node, if it’s leaf node, then update the result and since we are traversing level by level, the last stored right leaf will be the deepest right leaf node.

## C++

 `// CPP program to find deepest right leaf ` `// node of binary tree ` `#include ` `using` `namespace` `std; ` `  `  `// tree node ` `struct` `Node { ` `    ``int` `data; ` `    ``Node *left, *right; ` `}; ` `  `  `// returns a new tree Node ` `Node* newNode(``int` `data) ` `{ ` `    ``Node* temp = ``new` `Node(); ` `    ``temp->data = data; ` `    ``temp->left = temp->right = NULL; ` `    ``return` `temp; ` `} ` `  `  `// return the deepest right leaf node ` `// of binary tree ` `Node* getDeepestRightLeafNode(Node* root) ` `{ ` `    ``if` `(!root) ` `        ``return` `NULL; ` `  `  `    ``// create a queue for level order traversal ` `    ``queue q; ` `    ``q.push(root); ` `  `  `    ``Node* result = NULL; ` `  `  `    ``// traverse until the queue is empty ` `    ``while` `(!q.empty()) { ` `        ``Node* temp = q.front(); ` `        ``q.pop(); ` `  `  `         `  `        ``if` `(temp->left) { ` `            ``q.push(temp->left); ` `        ``} ` `         `  `        ``// Since we go level by level, the last  ` `        ``// stored right leaf node is deepest one  ` `        ``if` `(temp->right){ ` `            ``q.push(temp->right); ` `            ``if` `(!temp->right->left && !temp->right->right) ` `                ``result = temp->right; ` `        ``} ` `    ``} ` `    ``return` `result; ` `} ` `  `  `// driver program ` `int` `main() ` `{ ` `    ``// construct a tree ` `    ``Node* root = newNode(1); ` `    ``root->left = newNode(2); ` `    ``root->right = newNode(3); ` `    ``root->left->right = newNode(4); ` `    ``root->right->left = newNode(5); ` `    ``root->right->right = newNode(6); ` `    ``root->right->left->right = newNode(7); ` `    ``root->right->right->right = newNode(8); ` `    ``root->right->left->right->left = newNode(9); ` `    ``root->right->right->right->right = newNode(10); ` `  `  `    ``Node* result = getDeepestRightLeafNode(root); ` `    ``if` `(result) ` `        ``cout << ``"Deepest Right Leaf Node :: "` `             ``<< result->data << endl; ` `    ``else` `        ``cout << ``"No result, right leaf not found\n"``; ` `    ``return` `0; ` `} `

## Java

 `// Java program to find deepest right leaf ` `// node of binary tree ` `import` `java.util.*; ` ` `  `class` `GFG ` `{ ` ` `  ` `  `// tree node ` `static` `class` `Node  ` `{ ` `    ``int` `data; ` `    ``Node left, right; ` `}; ` ` `  `// returns a new tree Node ` `static` `Node newNode(``int` `data) ` `{ ` `    ``Node temp = ``new` `Node(); ` `    ``temp.data = data; ` `    ``temp.left = temp.right = ``null``; ` `    ``return` `temp; ` `} ` ` `  `// return the deepest right leaf node ` `// of binary tree ` `static` `Node getDeepestRightLeafNode(Node root) ` `{ ` `    ``if` `(root == ``null``) ` `        ``return` `null``; ` ` `  `    ``// create a queue for level order traversal ` `    ``Queue q = ``new` `LinkedList<>(); ` `    ``q.add(root); ` ` `  `    ``Node result = ``null``; ` ` `  `    ``// traverse until the queue is empty ` `    ``while` `(!q.isEmpty())  ` `    ``{ ` `        ``Node temp = q.peek(); ` `        ``q.poll(); ` ` `  `         `  `        ``if` `(temp.left != ``null``) ` `        ``{ ` `            ``q.add(temp.left); ` `        ``} ` `         `  `        ``// Since we go level by level, the last  ` `        ``// stored right leaf node is deepest one  ` `        ``if` `(temp.right != ``null``) ` `        ``{ ` `            ``q.add(temp.right); ` `            ``if` `(temp.right.left == ``null` `&& temp.right.right == ``null``) ` `                ``result = temp.right; ` `        ``} ` `    ``} ` `    ``return` `result; ` `} ` ` `  `// Driver code ` `public` `static` `void` `main(String[] args)  ` `{ ` `     `  `    ``// construct a tree ` `    ``Node root = newNode(``1``); ` `    ``root.left = newNode(``2``); ` `    ``root.right = newNode(``3``); ` `    ``root.left.right = newNode(``4``); ` `    ``root.right.left = newNode(``5``); ` `    ``root.right.right = newNode(``6``); ` `    ``root.right.left.right = newNode(``7``); ` `    ``root.right.right.right = newNode(``8``); ` `    ``root.right.left.right.left = newNode(``9``); ` `    ``root.right.right.right.right = newNode(``10``); ` ` `  `    ``Node result = getDeepestRightLeafNode(root); ` `    ``if` `(result != ``null``) ` `        ``System.out.println(``"Deepest Right Leaf Node :: "` `            ``+ result.data); ` `    ``else` `        ``System.out.println(``"No result, right leaf not found\n"``); ` `    ``} ` `} ` ` `  `/* This code is contributed by PrinciRaj1992 */`

## Python3

 `# Python3 program to find closest  ` `# value in Binary search Tree ` ` `  `_MIN ``=` `-``2147483648` `_MAX ``=` `2147483648` ` `  `# Helper function that allocates a new  ` `# node with the given data and None   ` `# left and right poers.                                      ` `class` `newnode:  ` ` `  `    ``# Constructor to create a new node  ` `    ``def` `__init__(``self``, data):  ` `        ``self``.data ``=` `data  ` `        ``self``.left ``=` `None` `        ``self``.right ``=` `None` ` `  `# utility function to return level  ` `# of given node ` `def` `getDeepestRightLeafNode(root) : ` ` `  `    ``if` `(``not` `root): ` `        ``return` `None` ` `  `    ``# create a queue for level  ` `    ``# order traversal  ` `    ``q ``=` `[]  ` `    ``q.append(root)  ` ` `  `    ``result ``=` `None` ` `  `    ``# traverse until the queue is empty  ` `    ``while` `(``len``(q)):  ` `        ``temp ``=` `q[``0``]  ` `        ``q.pop(``0``)  ` ` `  `        ``if` `(temp.left): ` `            ``q.append(temp.left)  ` `         `  `        ``# Since we go level by level, the last  ` `        ``# stored right leaf node is deepest one  ` `        ``if` `(temp.right):  ` `            ``q.append(temp.right)  ` `            ``if` `(``not` `temp.right.left ``and` `                ``not` `temp.right.right):  ` `                ``result ``=` `temp.right  ` ` `  `    ``return` `result ` ` `  `# Driver Code  ` `if` `__name__ ``=``=` `'__main__'``: ` `     `  `    ``# create a binary tree  ` `    ``root ``=` `newnode(``1``)  ` `    ``root.left ``=` `newnode(``2``)  ` `    ``root.right ``=` `newnode(``3``)  ` `    ``root.left.right ``=` `newnode(``4``) ` `    ``root.right.left ``=` `newnode(``5``)  ` `    ``root.right.right ``=` `newnode(``6``) ` `    ``root.right.left.right ``=` `newnode(``7``) ` `    ``root.right.right.right ``=` `newnode(``8``) ` `    ``root.right.left.right.left ``=` `newnode(``9``) ` `    ``root.right.right.right.right ``=` `newnode(``10``)  ` ` `  `    ``result ``=` `getDeepestRightLeafNode(root) ` `    ``if` `result: ` `        ``print``(``"Deepest Right Leaf Node ::"``, ` `                               ``result.data) ` `    ``else``: ` `        ``print``(``"No result, right leaf not found"``) ` `         `  `# This code is contributed by ` `# Shubham Singh(SHUBHAMSINGH10) `

## C#

 `// C# program to find deepest right leaf ` `// node of binary tree ` `using` `System; ` `using` `System.Collections.Generic;  ` `     `  `class` `GFG ` `{ ` ` `  ` `  `// tree node ` `public` `class` `Node  ` `{ ` `    ``public` `int` `data; ` `    ``public` `Node left, right; ` `}; ` ` `  `// returns a new tree Node ` `static` `Node newNode(``int` `data) ` `{ ` `    ``Node temp = ``new` `Node(); ` `    ``temp.data = data; ` `    ``temp.left = temp.right = ``null``; ` `    ``return` `temp; ` `} ` ` `  `// return the deepest right leaf node ` `// of binary tree ` `static` `Node getDeepestRightLeafNode(Node root) ` `{ ` `    ``if` `(root == ``null``) ` `        ``return` `null``; ` ` `  `    ``// Create a queue for level order traversal ` `    ``Queue q = ``new` `Queue(); ` `    ``q.Enqueue(root); ` ` `  `    ``Node result = ``null``; ` ` `  `    ``// Traverse until the queue is empty ` `    ``while` `(q.Count!=0)  ` `    ``{ ` `        ``Node temp = q.Peek(); ` `        ``q.Dequeue(); ` ` `  `         `  `        ``if` `(temp.left != ``null``) ` `        ``{ ` `            ``q.Enqueue(temp.left); ` `        ``} ` `         `  `        ``// Since we go level by level, the last  ` `        ``// stored right leaf node is deepest one  ` `        ``if` `(temp.right != ``null``) ` `        ``{ ` `            ``q.Enqueue(temp.right); ` `            ``if` `(temp.right.left == ``null` `&& temp.right.right == ``null``) ` `                ``result = temp.right; ` `        ``} ` `    ``} ` `    ``return` `result; ` `} ` ` `  `// Driver code ` `public` `static` `void` `Main(String[] args)  ` `{ ` `     `  `    ``// construct a tree ` `    ``Node root = newNode(1); ` `    ``root.left = newNode(2); ` `    ``root.right = newNode(3); ` `    ``root.left.right = newNode(4); ` `    ``root.right.left = newNode(5); ` `    ``root.right.right = newNode(6); ` `    ``root.right.left.right = newNode(7); ` `    ``root.right.right.right = newNode(8); ` `    ``root.right.left.right.left = newNode(9); ` `    ``root.right.right.right.right = newNode(10); ` ` `  `    ``Node result = getDeepestRightLeafNode(root); ` `    ``if` `(result != ``null``) ` `        ``Console.WriteLine(``"Deepest Right Leaf Node :: "` `            ``+ result.data); ` `    ``else` `        ``Console.WriteLine(``"No result, right leaf not found\n"``); ` `} ` `} ` ` `  `// This code is contributed by Princi Singh `

Output:

```Deepest Right Leaf Node :: 10
```

Time Complexity : O(n)

Mandeep Singh

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