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Find multiplication of sums of data of leaves at same levels

  • Difficulty Level : Easy
  • Last Updated : 11 Jun, 2021

Given a Binary Tree, return following value for it. 
1) For every level, compute sum of all leaves if there are leaves at this level. Otherwise, ignore it. 
2) Return multiplication of all sums.
Examples: 
 

Input: Root of below tree
         2
       /   \
      7     5
             \
              9
Output: 63
First levels doesn't have leaves. Second level
has one leaf 7 and third level also has one 
leaf 9.  Therefore result is 7*9 = 63


Input: Root of below tree
         2
       /   \
     7      5
    / \      \
   8   6      9
      / \    /  \
     1  11  4    10 

Output: 208
First two levels don't have leaves. Third
level has single leaf 8. Last level has four
leaves 1, 11, 4 and 10. Therefore result is 
8 * (1 + 11 + 4 + 10)  

We strongly recommend you to minimize your browser and try this yourself first.
One Simple Solution is to recursively compute leaf sum for all level starting from top to bottom. Then multiply sums of levels which have leaves. Time complexity of this solution would be O(n2).
An Efficient Solution is to use Queue based level order traversal. While doing the traversal, process all different levels separately. For every processed level, check if it has leaves. If it has then compute sum of leaf nodes. Finally return product of all sums.
 

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C++




/* Iterative C++ program to find sum of data of all leaves
   of a binary tree on same level and then multiply sums
   obtained of all levels. */
#include <bits/stdc++.h>
using namespace std;
 
// A Binary Tree Node
struct Node {
    int data;
    struct Node *left, *right;
};
 
// helper function to check if a Node is leaf of tree
bool isLeaf(Node* root)
{
    return (!root->left && !root->right);
}
 
/* Calculate sum of all leaf Nodes at each level and returns
   multiplication of sums */
int sumAndMultiplyLevelData(Node* root)
{
    // Tree is empty
    if (!root)
        return 0;
 
    int mul = 1; /* To store result */
 
    // Create an empty queue for level order traversal
    queue<Node*> q;
 
    // Enqueue Root and initialize height
    q.push(root);
 
    // Do level order traversal of tree
    while (1) {
        // NodeCount (queue size) indicates number of Nodes
        // at current level.
        int NodeCount = q.size();
 
        // If there are no Nodes at current level, we are done
        if (NodeCount == 0)
            break;
 
        // Initialize leaf sum for current level
        int levelSum = 0;
 
        // A boolean variable to indicate if found a leaf
        // Node at current level or not
        bool leafFound = false;
 
        // Dequeue all Nodes of current level and Enqueue all
        // Nodes of next level
        while (NodeCount > 0) {
            // Process next Node  of current level
            Node* Node = q.front();
 
            /* if Node is a leaf, update sum at the level */
            if (isLeaf(Node)) {
                leafFound = true;
                levelSum += Node->data;
            }
            q.pop();
 
            // Add children of Node
            if (Node->left != NULL)
                q.push(Node->left);
            if (Node->right != NULL)
                q.push(Node->right);
            NodeCount--;
        }
 
        // If we found at least one leaf, we multiply
        // result with level sum.
        if (leafFound)
            mul *= levelSum;
    }
 
    return mul; // Return result
}
 
// Utility function to create a new tree Node
Node* newNode(int data)
{
    Node* temp = new Node;
    temp->data = data;
    temp->left = temp->right = NULL;
    return temp;
}
 
// Driver program to test above functions
int main()
{
    Node* root = newNode(2);
    root->left = newNode(7);
    root->right = newNode(5);
    root->left->right = newNode(6);
    root->left->left = newNode(8);
    root->left->right->left = newNode(1);
    root->left->right->right = newNode(11);
    root->right->right = newNode(9);
    root->right->right->left = newNode(4);
    root->right->right->right = newNode(10);
 
    cout << "Final product value = "
         << sumAndMultiplyLevelData(root) << endl;
 
    return 0;
}

Java




/* Iterative Java program to find sum of data of all leaves
   of a binary tree on same level and then multiply sums
   obtained of all levels. */
 
/* importing the necessary class */
import java.util.LinkedList;
import java.util.Queue;
import java.util.Stack;
 
/* Class containing left and right child of current
 node and key value*/
class Node {
 
    int data;
    Node left, right;
 
    public Node(int item)
    {
        data = item;
        left = right = null;
    }
}
 
class BinaryTree {
 
    Node root;
 
    // helper function to check if a Node is leaf of tree
    boolean isLeaf(Node node)
    {
        return ((node.left == null) && (node.right == null));
    }
 
    /* Calculate sum of all leaf Nodes at each level and returns
     multiplication of sums */
    int sumAndMultiplyLevelData()
    {
        return sumAndMultiplyLevelData(root);
    }
    int sumAndMultiplyLevelData(Node node)
    {
        // Tree is empty
        if (node == null) {
            return 0;
        }
 
        int mul = 1; /* To store result */
 
        // Create an empty queue for level order traversal
        LinkedList<Node> q = new LinkedList<Node>();
 
        // Enqueue Root and initialize height
        q.add(node);
 
        // Do level order traversal of tree
        while (true) {
 
            // NodeCount (queue size) indicates number of Nodes
            // at current level.
            int NodeCount = q.size();
 
            // If there are no Nodes at current level, we are done
            if (NodeCount == 0) {
                break;
            }
 
            // Initialize leaf sum for current level
            int levelSum = 0;
 
            // A boolean variable to indicate if found a leaf
            // Node at current level or not
            boolean leafFound = false;
 
            // Dequeue all Nodes of current level and Enqueue all
            // Nodes of next level
            while (NodeCount > 0) {
                Node node1;
                node1 = q.poll();
 
                /* if Node is a leaf, update sum at the level */
                if (isLeaf(node1)) {
                    leafFound = true;
                    levelSum += node1.data;
                }
 
                // Add children of Node
                if (node1.left != null) {
                    q.add(node1.left);
                }
                if (node1.right != null) {
                    q.add(node1.right);
                }
                NodeCount--;
            }
 
            // If we found at least one leaf, we multiply
            // result with level sum.
            if (leafFound) {
                mul *= levelSum;
            }
        }
 
        return mul; // Return result
    }
 
    public static void main(String args[])
    {
 
        /* creating a binary tree and entering
         the nodes */
        BinaryTree tree = new BinaryTree();
        tree.root = new Node(2);
        tree.root.left = new Node(7);
        tree.root.right = new Node(5);
        tree.root.left.left = new Node(8);
        tree.root.left.right = new Node(6);
        tree.root.left.right.left = new Node(1);
        tree.root.left.right.right = new Node(11);
        tree.root.right.right = new Node(9);
        tree.root.right.right.left = new Node(4);
        tree.root.right.right.right = new Node(10);
        System.out.println("The final product value : "
                           + tree.sumAndMultiplyLevelData());
    }
}
 
// This code is contributed by Mayank Jaiswal

Python3




"""Iterative Python3 program to find
sum of data of all leaves of a binary
tree on same level and then multiply
sums obtained of all levels."""
 
# A Binary Tree Node
# Utility function to create a
# new tree Node
class newNode:
    def __init__(self, data):
        self.data = data
        self.left = self.right = None
         
# helper function to check if a
# Node is leaf of tree
def isLeaf(root) :
 
    return (not root.left and
            not root.right)
 
""" Calculate sum of all leaf Nodes at each
level and returns multiplication of sums """
def sumAndMultiplyLevelData( root) :
 
    # Tree is empty
    if (not root) :
        return 0
 
    mul = 1
     
    """ To store result """
    # Create an empty queue for level
    # order traversal
    q = []
 
    # Enqueue Root and initialize height
    q.append(root)
 
    # Do level order traversal of tree
    while (1):
         
        # NodeCount (queue size) indicates
        # number of Nodes at current level.
        NodeCount = len(q)
 
        # If there are no Nodes at current
        # level, we are done
        if (NodeCount == 0) :
            break
 
        # Initialize leaf sum for
        # current level
        levelSum = 0
 
        # A boolean variable to indicate
        # if found a leaf Node at current
        # level or not
        leafFound = False
 
        # Dequeue all Nodes of current level
        # and Enqueue all Nodes of next level
        while (NodeCount > 0) :
             
            # Process next Node of current level
            Node = q[0]
 
            """ if Node is a leaf, update
                sum at the level """
            if (isLeaf(Node)) :
                leafFound = True
                levelSum += Node.data
 
            q.pop(0)
 
            # Add children of Node
            if (Node.left != None) :
                q.append(Node.left)
            if (Node.right != None) :
                q.append(Node.right)
            NodeCount-=1
                 
        # If we found at least one leaf,
        # we multiply result with level sum.
        if (leafFound) :
            mul *= levelSum
     
    return mul # Return result
 
# Driver Code
if __name__ == '__main__':
    root = newNode(2)
    root.left = newNode(7)
    root.right = newNode(5)
    root.left.right = newNode(6)
    root.left.left = newNode(8)
    root.left.right.left = newNode(1)
    root.left.right.right = newNode(11)
    root.right.right = newNode(9)
    root.right.right.left = newNode(4)
    root.right.right.right = newNode(10)
 
    print("Final product value = ",
           sumAndMultiplyLevelData(root))
 
# This code is contributed
# by SHUBHAMSINGH10

C#




/* Iterative C# program to find sum
of data of all leaves of a binary tree
on same level and then multiply sums
obtained of all levels. */
 
/* importing the necessary class */
using System;
using System.Collections.Generic;
 
/* Class containing left and right child
 of current node and key value*/
public class Node
{
 
    public int data;
    public Node left, right;
 
    public Node(int item)
    {
        data = item;
        left = right = null;
    }
}
 
public class BinaryTree
{
 
    Node root;
 
    // helper function to check if
    // a Node is leaf of tree
    bool isLeaf(Node node)
    {
        return ((node.left == null) &&
                (node.right == null));
    }
 
    /* Calculate sum of all leaf
    Nodes at each level and returns
    multiplication of sums */
    int sumAndMultiplyLevelData()
    {
        return sumAndMultiplyLevelData(root);
    }
    int sumAndMultiplyLevelData(Node node)
    {
        // Tree is empty
        if (node == null) {
            return 0;
        }
 
        int mul = 1; /* To store result */
 
        // Create an empty queue for level order traversal
        Queue<Node> q = new Queue<Node>();
 
        // Enqueue Root and initialize height
        q.Enqueue(node);
 
        // Do level order traversal of tree
        while (true) {
 
            // NodeCount (queue size) indicates
            // number of Nodes at current level.
            int NodeCount = q.Count;
 
            // If there are no Nodes at current
            // level, we are done
            if (NodeCount == 0)
            {
                break;
            }
 
            // Initialize leaf sum for current level
            int levelSum = 0;
 
            // A boolean variable to indicate if found a leaf
            // Node at current level or not
            bool leafFound = false;
 
            // Dequeue all Nodes of current level and
            // Enqueue all Nodes of next level
            while (NodeCount > 0)
            {
                Node node1;
                node1 = q.Dequeue();
 
                /* if Node is a leaf, update sum at the level */
                if (isLeaf(node1))
                {
                    leafFound = true;
                    levelSum += node1.data;
                }
 
                // Add children of Node
                if (node1.left != null)
                {
                    q.Enqueue(node1.left);
                }
                if (node1.right != null)
                {
                    q.Enqueue(node1.right);
                }
                NodeCount--;
            }
 
            // If we found at least one leaf, we multiply
            // result with level sum.
            if (leafFound)
            {
                mul *= levelSum;
            }
        }
 
        return mul; // Return result
    }
 
    // Driver code
    public static void Main(String []args)
    {
 
        /* creating a binary tree and entering
        the nodes */
        BinaryTree tree = new BinaryTree();
        tree.root = new Node(2);
        tree.root.left = new Node(7);
        tree.root.right = new Node(5);
        tree.root.left.left = new Node(8);
        tree.root.left.right = new Node(6);
        tree.root.left.right.left = new Node(1);
        tree.root.left.right.right = new Node(11);
        tree.root.right.right = new Node(9);
        tree.root.right.right.left = new Node(4);
        tree.root.right.right.right = new Node(10);
        Console.WriteLine("The final product value : "
                        + tree.sumAndMultiplyLevelData());
    }
}
 
// This code has been contributed by 29AjayKumar

Javascript




<script>
 
/* Iterative Javascript program to
   find sum of data of all leaves
   of a binary tree on same level
   and then multiply sums
   obtained of all levels. */
  
/* importing the necessary class */
 
/* Class containing left and right child of current
 node and key value*/
class Node
{
    constructor(data)
    {
        this.data=data;
        this.left = this.right = null;
    }
}
 
let root;
// helper function to check if a Node is leaf of tree
function isLeaf(node)
{
    return ((node.left == null) && (node.right == null));
}
 
/* Calculate sum of all leaf Nodes at each level and returns
     multiplication of sums */   
 
 
function sumAndMultiplyLevelData(node)
{
     // Tree is empty
        if (node == null) {
            return 0;
        }
  
        let mul = 1; /* To store result */
  
        // Create an empty queue for level order traversal
        let q = [];
  
        // Enqueue Root and initialize height
        q.push(node);
  
        // Do level order traversal of tree
        while (true) {
  
            // NodeCount (queue size) indicates number of Nodes
            // at current level.
            let NodeCount = q.length;
  
            // If there are no Nodes at current level, we are done
            if (NodeCount == 0) {
                break;
            }
  
            // Initialize leaf sum for current level
            let levelSum = 0;
  
            // A boolean variable to indicate if found a leaf
            // Node at current level or not
            let leafFound = false;
  
            // Dequeue all Nodes of current level and Enqueue all
            // Nodes of next level
            while (NodeCount > 0) {
                 
                let node1= q.shift();
  
                /* if Node is a leaf, update sum at the level */
                if (isLeaf(node1)) {
                    leafFound = true;
                    levelSum += node1.data;
                }
  
                // Add children of Node
                if (node1.left != null) {
                    q.push(node1.left);
                }
                if (node1.right != null) {
                    q.push(node1.right);
                }
                NodeCount--;
            }
  
            // If we found at least one leaf, we multiply
            // result with level sum.
            if (leafFound) {
                mul *= levelSum;
            }
        }
  
        return mul; // Return result
}
 
/* creating a binary tree and entering
         the nodes */
root = new Node(2);
root.left = new Node(7);
root.right = new Node(5);
root.left.left = new Node(8);
root.left.right = new Node(6);
root.left.right.left = new Node(1);
root.left.right.right = new Node(11);
root.right.right = new Node(9);
root.right.right.left = new Node(4);
root.right.right.right = new Node(10);
document.write("The final product value : "
                   + sumAndMultiplyLevelData(root));
 
 
 
// This code is contributed by rag2127
 
</script>

Output:  



Final product value = 208

 

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




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