Sum of nodes at maximum depth of a Binary Tree | Set 2

Given a root node to a tree, find the sum of all the leaf nodes which are at maximum depth from root node.

Example:

      1
    /   \
   2     3
  / \   / \
 4   5 6   7

Input : root(of above tree)
Output : 22

Explanation:
Nodes at maximum depth are: 4, 5, 6, 7. 
So, sum of these nodes = 22

In the previous article we discussed a recursive solution which first finds the maximum level and then finds the sum of all nodes present at that level.



In this article we will see a recursive solution without finding the height or depth. The idea is that while traversing the nodes compare the level of the node with max_level (Maximum level till the current node). If the current level exceeds the maximum level, update the max_level as current level. If the max level and current level are same, add the root data to current sum otherwise if level is less than max_level, do nothing.

Below is the implementation of the above approach:

C++

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// C++ Program to find sum of nodes at maximum
// Depth of the Binary Tree
  
#include <bits/stdc++.h>
using namespace std;
  
// Variables to store sum and
// maximum level
int sum = 0, max_level = INT_MIN;
  
// Binary Tree Node
struct Node {
    int data;
    Node* left;
    Node* right;
};
  
// Utility function to create and
// return a new Binary Tree Node
Node* createNode(int val)
{
  
    Node* node = new Node;
  
    node->data = val;
    node->left = NULL;
    node->right = NULL;
  
    return node;
}
  
// Function to find the sum of the node which
// are present at the maximum depth
void sumOfNodesAtMaxDepth(Node* root, int level)
{
    if (root == NULL)
        return;
  
    // If the current level exceeds the
    // maximum level, update the max_level
    // as current level.
    if (level > max_level) {
        sum = root->data;
        max_level = level;
    }
  
    // If the max level and current level
    // are same, add the root data to
    // current sum.
    else if (level == max_level) {
        sum = sum + root->data;
    }
  
    // Traverse the left and right subtrees
    sumOfNodesAtMaxDepth(root->left, level + 1);
    sumOfNodesAtMaxDepth(root->right, level + 1);
}
  
// Driver Code
int main()
{
    Node* root;
    root = createNode(1);
    root->left = createNode(2);
    root->right = createNode(3);
    root->left->left = createNode(4);
    root->left->right = createNode(5);
    root->right->left = createNode(6);
    root->right->right = createNode(7);
  
    sumOfNodesAtMaxDepth(root, 0);
  
    cout << sum;
  
    return 0;
}

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Java














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// Java Program to find sum of nodes at maximum  


// Depth of the Binary Tree  


  


class GfG  


{ 


  


// Variables to store sum and  


// maximum level  


static int sum = 0, 


    max_level = Integer.MIN_VALUE;  


  


// Binary Tree Node  


static class Node  


{  


    int data;  


    Node left;  


    Node right;  


} 


  


// Utility function to create and  


// return a new Binary Tree Node  


static Node createNode(int val)  


{  


  


    Node node = new Node();  


    node.data = val;  


    node.left = null;  


    node.right = null;  


  


    return node;  


}  


  


// Function to find the sum of  


// the node which are present 


// at the maximum depth  


static void sumOfNodesAtMaxDepth(Node root,  


                                int level)  


{  


    if (root == null)  


        return;  


  


    // If the current level exceeds the  


    // maximum level, update the max_level  


    // as current level.  


    if (level > max_level)  


    {  


        sum = root.data;  


        max_level = level;  


    }  


  


    // If the max level and current level  


    // are same, add the root data to  


    // current sum.  


    else if (level == max_level)  


    {  


        sum = sum + root.data;  


    }  


  


    // Traverse the left and right subtrees  


    sumOfNodesAtMaxDepth(root.left, level + 1);  


    sumOfNodesAtMaxDepth(root.right, level + 1);  


}  


  


// Driver Code  


public static void main(String[] args)  


{  


    Node root = null;  


    root = createNode(1);  


    root.left = createNode(2);  


    root.right = createNode(3);  


    root.left.left = createNode(4);  


    root.left.right = createNode(5);  


    root.right.left = createNode(6);  


    root.right.right = createNode(7);  


  


    sumOfNodesAtMaxDepth(root, 0);  


    System.out.println(sum);  


} 


}  


  


// This code is contributed by  


// Prerna Saini. 



















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Python3














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# Python3 Program to find sum of nodes at maximum 


# Depth of the Binary Tree 


  


# Variables to store sum and 


# maximum level 


sum = [0] 


max_level = [-(2**32)] 


  


# Binary tree node  


class createNode:  


      


    def __init__(self, data):  


        self.data = data  


        self.left = None


        self.right = None


  


# Function to find the sum of the node which 


# are present at the maximum depth 


def sumOfNodesAtMaxDepth(root, level): 


    if (root == None): 


        return


      


    # If the current level exceeds the 


    # maximum level, update the max_level 


    # as current level. 


    if (level > max_level[0]): 


        sum[0] = root.data 


        max_level[0] = level 


          


    # If the max level and current level 


    #are same, add the root data to 


    # current sum. 


    elif (level == max_level[0]): 


        sum[0] = sum[0] + root.data 


          


    # Traverse the left and right subtrees 


    sumOfNodesAtMaxDepth(root.left, level + 1) 


    sumOfNodesAtMaxDepth(root.right, level + 1) 


      


# Driver Code 


root = createNode(1) 


root.left = createNode(2) 


root.right = createNode(3) 


root.left.left = createNode(4) 


root.left.right = createNode(5) 


root.right.left = createNode(6) 


root.right.right = createNode(7) 


  


sumOfNodesAtMaxDepth(root, 0) 


  


print(sum[0]) 


  


# This code is contributed by SHUBHAMSINGH10 



















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C#














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// C#  Program to find sum of nodes at maximum  


// Depth of the Binary Tree 


using System; 


public class GfG  


{  


  


    // Variables to store sum and  


    // maximum level  


    static int sum = 0,  


        max_level = int.MinValue;  


  


    // Binary Tree Node  


    class Node  


    {  


        public int data;  


        public Node left;  


        public Node right;  


    }  


  


    // Utility function to create and  


    // return a new Binary Tree Node  


    static Node createNode(int val)  


    {  


  


        Node node = new Node();  


        node.data = val;  


        node.left = null;  


        node.right = null;  


  


        return node;  


    }  


  


    // Function to find the sum of  


    // the node which are present  


    // at the maximum depth  


    static void sumOfNodesAtMaxDepth(Node root,  


                                    int level)  


    {  


        if (root == null)  


            return;  


  


        // If the current level exceeds the  


        // maximum level, update the max_level  


        // as current level.  


        if (level > max_level)  


        {  


            sum = root.data;  


            max_level = level;  


        }  


  


        // If the max level and current level  


        // are same, add the root data to  


        // current sum.  


        else if (level == max_level)  


        {  


            sum = sum + root.data;  


        }  


  


        // Traverse the left and right subtrees  


        sumOfNodesAtMaxDepth(root.left, level + 1);  


        sumOfNodesAtMaxDepth(root.right, level + 1);  


    }  


  


    // Driver Code  


    public static void Main()  


    {  


        Node root = null;  


        root = createNode(1);  


        root.left = createNode(2);  


        root.right = createNode(3);  


        root.left.left = createNode(4);  


        root.left.right = createNode(5);  


        root.right.left = createNode(6);  


        root.right.right = createNode(7);  


  


        sumOfNodesAtMaxDepth(root, 0);  


        Console.WriteLine(sum);  


    }  


}  


  


/* This code is contributed PrinciRaj1992 */



















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Output:


22








    

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