Find depth of the deepest odd level leaf node

Write a code to get the depth of the deepest odd level leaf node in a binary tree. Consider that level starts with 1. Depth of a leaf node is number of nodes on the path from root to leaf (including both leaf and root).

For example, consider the following tree. The deepest odd level node is the node with value 9 and depth of this node is 5.

       1
     /   \
    2     3
  /      /  \  
 4      5    6
        \     \
         7     8
        /       \
       9         10
                 /
                11

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

The idea is to recursively traverse the given binary tree and while traversing, maintain a variable “level” which will store the current node’s level in the tree. If current node is leaf then check “level” is odd or not. If level is odd then return it. If current node is not leaf, then recursively find maximum depth in left and right subtrees, and return maximum of the two depths.

C++

// C++ program to find depth of the 
// deepest odd level leaf node 
#include <bits/stdc++.h> 
using namespace std; 
  
// A utility function to find  
// maximum of two integers 
int max(int x, int y)  
{  
    return (x > y)? x : y;  
} 
  
// A Binary Tree node 
struct Node 
{ 
    int data; 
    struct Node *left, *right; 
}; 
  
// A utility function to allocate a 
// new tree node 
struct Node* newNode(int data) 
{ 
    struct Node* node = (struct Node*) malloc(sizeof(struct Node)); 
    node->data = data; 
    node->left = node->right = NULL; 
    return node; 
} 
  
// A recursive function to find depth of 
// the deepest odd level leaf 
int depthOfOddLeafUtil(struct Node *root, 
                               int level) 
{ 
    // Base Case 
    if (root == NULL) 
        return 0; 
  
    // If this node is a leaf and its level 
    // is odd, return its level 
    if (root->left == NULL &&  
        root->right == NULL && level & 1) 
        return level; 
  
    // If not leaf, return the maximum value 
    // from left and right subtrees 
    return max(depthOfOddLeafUtil(root->left, level + 1), 
               depthOfOddLeafUtil(root->right, level + 1)); 
} 
  
/* Main function which calculates the depth 
   of deepest odd level leaf. This function 
   mainly uses depthOfOddLeafUtil() */
int depthOfOddLeaf(struct Node *root) 
{ 
    int level = 1, depth = 0; 
    return depthOfOddLeafUtil(root, level); 
} 
  
// Driver Code 
int main() 
{ 
    struct 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(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); 
    root->right->right->right->right->left = newNode(11); 
  
    cout << depthOfOddLeaf(root)  
         << " is the required depth"; 
    getchar(); 
    return 0; 
} 
  
// This code is contributed 
// by Akanksha Rai 

C

// C program to find depth of the deepest odd level leaf node 
#include <stdio.h> 
#include <stdlib.h> 
  
// A utility function to find maximum of two integers 
int max(int x, int y) { return (x > y)? x : y; } 
  
// A Binary Tree node 
struct Node 
{ 
    int data; 
    struct Node *left, *right; 
}; 
  
// A utility function to allocate a new tree node 
struct Node* newNode(int data) 
{ 
    struct Node* node = (struct Node*) malloc(sizeof(struct Node)); 
    node->data = data; 
    node->left = node->right = NULL; 
    return node; 
} 
  
// A recursive function to find depth of the deepest odd level leaf 
int depthOfOddLeafUtil(struct Node *root,int level) 
{ 
    // Base Case 
    if (root == NULL) 
        return 0; 
  
    // If this node is a leaf and its level is odd, return its level 
    if (root->left==NULL && root->right==NULL && level&1) 
        return level; 
  
    // If not leaf, return the maximum value from left and right subtrees 
    return max(depthOfOddLeafUtil(root->left, level+1), 
            depthOfOddLeafUtil(root->right, level+1)); 
} 
  
/* Main function which calculates the depth of deepest odd level leaf. 
This function mainly uses depthOfOddLeafUtil() */
int depthOfOddLeaf(struct Node *root) 
{ 
    int level = 1, depth = 0; 
    return depthOfOddLeafUtil(root, level); 
} 
  
// Driver program to test above functions 
int main() 
{ 
    struct 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(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); 
    root->right->right->right->right->left = newNode(11); 
  
    printf("%d is the required depth\n", depthOfOddLeaf(root)); 
    getchar(); 
    return 0; 
} 

Java

// Java program to find depth of deepest odd level node 
  
// A binary tree node 
class Node  
{ 
    int data; 
    Node left, right; 
   
    Node(int item)  
    { 
        data = item; 
        left = right = null; 
    } 
} 
   
class BinaryTree  
{ 
    Node root; 
   
    // A recursive function to find depth of the deepest odd level leaf 
    int depthOfOddLeafUtil(Node node, int level)  
    { 
        // Base Case 
        if (node == null) 
            return 0; 
   
        // If this node is a leaf and its level is odd, return its level 
        if (node.left == null && node.right == null && (level & 1) != 0) 
            return level; 
   
        // If not leaf, return the maximum value from left and right subtrees 
        return Math.max(depthOfOddLeafUtil(node.left, level + 1), 
                depthOfOddLeafUtil(node.right, level + 1)); 
    } 
   
    /* Main function which calculates the depth of deepest odd level leaf. 
       This function mainly uses depthOfOddLeafUtil() */
    int depthOfOddLeaf(Node node)  
    { 
        int level = 1, depth = 0; 
        return depthOfOddLeafUtil(node, level); 
    } 
   
    public static void main(String args[])  
    { 
        int k = 45; 
        BinaryTree tree = new BinaryTree(); 
        tree.root = new Node(1); 
        tree.root.left = new Node(2); 
        tree.root.right = new Node(3); 
        tree.root.left.left = new Node(4); 
        tree.root.right.left = new Node(5); 
        tree.root.right.right = new Node(6); 
        tree.root.right.left.right = new Node(7); 
        tree.root.right.right.right = new Node(8); 
        tree.root.right.left.right.left = new Node(9); 
        tree.root.right.right.right.right = new Node(10); 
        tree.root.right.right.right.right.left = new Node(11); 
        System.out.println(tree.depthOfOddLeaf(tree.root) +  
                                                   " is the required depth"); 
    } 
} 
   
// This code has been contributed by Mayank Jaiswal 

Python

# Python program to find depth of the deepest odd level 
# leaf node 
  
# A Binary tree node 
class Node: 
      
    # Constructor to create a new node 
    def __init__(self, data): 
        self.data = data 
        self.left = None
        self.right = None
  
# A recursive function to find depth of the deepest  
# odd level leaf node 
def depthOfOddLeafUtil(root, level): 
      
    # Base Case 
    if root is None: 
        return 0 
  
    # If this node is leaf and its level is odd, return 
    # its level 
    if root.left is None and root.right is None and level&1:  
        return level  
      
    # If not leaf, return the maximum value from left 
    # and right subtrees 
    return (max(depthOfOddLeafUtil(root.left, level+1), 
                depthOfOddLeafUtil(root.right, level+1))) 
  
# Main function which calculates the depth of deepest odd 
# level leaf .  
# This function mainly uses depthOfOddLeafUtil() 
def depthOfOddLeaf(root): 
    level = 1 
    depth = 0
    return depthOfOddLeafUtil(root, level) 
  
# Driver program to test above function 
root = Node(1) 
root.left = Node(2) 
root.right = Node(3) 
root.left.left = Node(4) 
root.right.left = Node(5) 
root.right.right = Node(6) 
root.right.left.right = Node(7) 
root.right.right.right = Node(8) 
root.right.left.right.left = Node(9) 
root.right.right.right.right = Node(10) 
root.right.right.right.right.left= Node(11) 
  
print "%d is the required depth" %(depthOfOddLeaf(root)) 
  
# This code is contributed by Nikhil Kumar Singh(nickzuck_007) 

C#

using System; 
  
// C# program to find depth of deepest odd level node  
  
// A binary tree node  
public class Node 
{ 
    public int data; 
    public Node left, right; 
  
    public Node(int item) 
    { 
        data = item; 
        left = right = null; 
    } 
} 
  
public class BinaryTree 
{ 
    public Node root; 
  
    // A recursive function to find depth of the deepest odd level leaf  
    public virtual int depthOfOddLeafUtil(Node node, int level) 
    { 
        // Base Case  
        if (node == null) 
        { 
            return 0; 
        } 
  
        // If this node is a leaf and its level is odd, return its level  
        if (node.left == null && node.right == null && (level & 1) != 0) 
        { 
            return level; 
        } 
  
        // If not leaf, return the maximum value from left and right subtrees  
        return Math.Max(depthOfOddLeafUtil(node.left, level + 1), 
                        depthOfOddLeafUtil(node.right, level + 1)); 
    } 
  
    /* Main function which calculates the depth of deepest odd level leaf.  
    This function mainly uses depthOfOddLeafUtil() */
    public virtual int depthOfOddLeaf(Node node) 
    { 
        int level = 1, depth = 0; 
        return depthOfOddLeafUtil(node, level); 
    } 
  
    public static void Main(string[] args) 
    { 
        int k = 45; 
        BinaryTree tree = new BinaryTree(); 
        tree.root = new Node(1); 
        tree.root.left = new Node(2); 
        tree.root.right = new Node(3); 
        tree.root.left.left = new Node(4); 
        tree.root.right.left = new Node(5); 
        tree.root.right.right = new Node(6); 
        tree.root.right.left.right = new Node(7); 
        tree.root.right.right.right = new Node(8); 
        tree.root.right.left.right.left = new Node(9); 
        tree.root.right.right.right.right = new Node(10); 
        tree.root.right.right.right.right.left = new Node(11); 
        Console.WriteLine(tree.depthOfOddLeaf(tree.root) + " is the required depth"); 
    } 
} 
  
// This code is contributed by Shrikant13 

Output:

5 is the required depth

Time Complexity: The function does a simple traversal of the tree, so the complexity is O(n).

Iterative Approach
This approach is contributed by Mandeep Singh. Traverse the tree in iterative fashion for each level, and whenever you encounter the leaf node, check if level is odd, if level is odd, then update the result.

C++

// CPP program to find 
// depth of the deepest 
// odd level leaf node 
// of binary tree 
#include <bits/stdc++.h> 
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 max odd number 
// depth of leaf node 
int maxOddLevelDepth(Node* root) 
{ 
    if (!root) 
        return 0; 
  
    // create a queue 
    // for level order  
    // traversal 
    queue<Node*> q; 
    q.push(root); 
  
    int result = INT_MAX; 
    int level = 0; 
  
    // traverse until the 
    // queue is empty 
    while (!q.empty())  
    { 
        int size = q.size(); 
        level += 1; 
  
        // traverse for 
        // complete level 
        while(size > 0) 
        { 
            Node* temp = q.front(); 
            q.pop(); 
  
            // check if the node is 
            // leaf node and level  
            // is odd if level is 
            // odd, then update result 
            if(!temp->left && !temp->right  
                      && (level % 2 != 0)) 
            { 
                result = level; 
            } 
          
            // check for left child 
            if (temp->left)  
            { 
                q.push(temp->left); 
            } 
              
            // check for right child 
            if (temp->right) 
            { 
                q.push(temp->right); 
            } 
            size -= 1; 
        }  
    } 
      
    return result; 
} 
  
// driver program 
int main() 
{ 
    // construct a tree 
    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(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); 
    root->right->right->right->right->left = newNode(11); 
  
    int result = maxOddLevelDepth(root); 
      
    if (result == INT_MAX) 
        cout << "No leaf node at odd level\n"; 
    else
        cout << result; 
        cout << " is the required depth " << endl; 
    return 0; 
} 

Java

// Java program to find depth of the deepest 
// odd level 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 max odd number depth of leaf node 
static int maxOddLevelDepth(Node root) 
{ 
    if (root == null) 
        return 0; 
  
    // create a queue for level order  
    // traversal 
    Queue<Node> q = new LinkedList<>(); 
    q.add(root); 
  
    int result = Integer.MAX_VALUE; 
    int level = 0; 
  
    // traverse until the queue is empty 
    while (!q.isEmpty())  
    { 
        int size = q.size(); 
        level += 1; 
  
        // traverse for complete level 
        while(size > 0) 
        { 
            Node temp = q.peek(); 
            q.remove(); 
  
            // check if the node is leaf node and  
            // level is odd if level is odd, 
            // then update result 
            if(temp.left == null &&  
               temp.right == null && (level % 2 != 0)) 
            { 
                result = level; 
            } 
          
            // check for left child 
            if (temp.left != null)  
            { 
                q.add(temp.left); 
            } 
              
            // check for right child 
            if (temp.right != null) 
            { 
                q.add(temp.right); 
            } 
            size -= 1; 
        }  
    } 
    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.left = 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); 
    root.right.right.right.right.left = newNode(11); 
  
    int result = maxOddLevelDepth(root); 
      
    if (result == Integer.MAX_VALUE) 
        System.out.println("No leaf node at odd level"); 
    else
    { 
        System.out.print(result); 
        System.out.println(" is the required depth "); 
    } 
} 
} 
  
// This code is contributed by Rajput-Ji 

Python3

# Python3 program to find depth of the deepest  
# odd level leaf node of binary tree 
  
INT_MAX = 2**31
  
# tree node returns a new tree Node 
class newNode:  
    def __init__(self, data):  
        self.data = data  
        self.left = self.right = None
          
# return max odd number depth  
# of leaf node  
def maxOddLevelDepth(root) : 
  
    if (not root):  
        return 0
  
    # create a queue for level order  
    # traversal  
    q = []  
    q.append(root)  
  
    result = INT_MAX  
    level = 0
  
    # traverse until the queue is empty  
    while (len(q)) : 
      
        size = len(q)  
        level += 1
  
        # traverse for complete level  
        while(size > 0) : 
          
            temp = q[0]  
            q.pop(0)  
  
            # check if the node is leaf node  
            # and level is odd if level is  
            # odd, then update result  
            if(not temp.left and not temp.right  
                    and (level % 2 != 0)) : 
              
                result = level  
              
            # check for left child  
            if (temp.left) : 
              
                q.append(temp.left)  
              
            # check for right child  
            if (temp.right) : 
              
                q.append(temp.right)  
              
            size -= 1
      
    return result  
  
# Driver Code  
if __name__ == '__main__': 
    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(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)  
    root.right.right.right.right.left = newNode(11)  
  
    result = maxOddLevelDepth(root)  
    if (result == INT_MAX) : 
        print("No leaf node at odd level")  
    else: 
        print(result, end = "") 
        print(" is the required depth ") 
          
# This code is contributed 
# by SHUBHAMSINGH10 

C#

// C# program to find depth of the deepest 
// odd level 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 max odd number depth of leaf node 
static int maxOddLevelDepth(Node root) 
{ 
    if (root == null) 
        return 0; 
  
    // create a queue for level order  
    // traversal 
    Queue<Node> q = new Queue<Node>(); 
    q.Enqueue(root); 
  
    int result = int.MaxValue; 
    int level = 0; 
  
    // traverse until the queue is empty 
    while (q.Count != 0)  
    { 
        int size = q.Count; 
        level += 1; 
  
        // traverse for complete level 
        while(size > 0) 
        { 
            Node temp = q.Peek(); 
            q.Dequeue(); 
  
            // check if the node is leaf node and  
            // level is odd if level is odd, 
            // then update result 
            if(temp.left == null &&  
               temp.right == null && 
              (level % 2 != 0)) 
            { 
                result = level; 
            } 
          
            // check for left child 
            if (temp.left != null)  
            { 
                q.Enqueue(temp.left); 
            } 
              
            // check for right child 
            if (temp.right != null) 
            { 
                q.Enqueue(temp.right); 
            } 
            size -= 1; 
        }  
    } 
    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.left = 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); 
    root.right.right.right.right.left = newNode(11); 
  
    int result = maxOddLevelDepth(root); 
      
    if (result == int.MaxValue) 
        Console.WriteLine("No leaf node at odd level"); 
    else
    { 
        Console.Write(result); 
        Console.WriteLine(" is the required depth "); 
    } 
} 
} 
  
// This code is contributed by PrinciRaj1992 

Output:

5 is the required depth

Time Complexity: Time Complexity is O(n).

This article is contributed by Chandra Prakash. Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.

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My Personal Notes

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

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