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Sum of heights of all individual nodes in a binary tree

  • Difficulty Level : Easy
  • Last Updated : 26 May, 2021
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Given a binary tree, find the sum of heights of all individual nodes in the tree.

Example:

Binary Tree

For this tree:
1). Height of Node 1 - 3
2). Height of Node 2 - 2
3). Height of Node 3 - 1
4). Height of Node 4 - 1
5). Height of Node 5 - 1

Adding all of them = 8

Prerequisites:- Height of binary tree

Simple Solution:



We get the height of all individual nodes by parsing the tree in any of the following methods, i.e. Inorder, postorder, preorder(I performed inorder tree traversal), and getting their heights using the getHeight function, which checks both left and right subtree and returns the maximum of them. Finally, we add up all the individual heights.

C++




// C++ program to find sum of heights of all
// nodes in a binary tree
#include <bits/stdc++.h>
 
/* 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;
};
 
/* Compute the "maxHeight" of a particular Node*/
int getHeight(struct Node* Node)
{
    if (Node == NULL)
        return 0;
    else {
        /* compute the height of each subtree */
        int lHeight = getHeight(Node->left);
        int rHeight = getHeight(Node->right);
 
        /* use the larger one */
        if (lHeight > rHeight)
            return (lHeight + 1);
        else
            return (rHeight + 1);
    }
}
 
/* Helper function that allocates a new Node with the
   given data and NULL left and right pointers. */
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 sum of heights of individual Nodes
   Uses Inorder traversal */
int getTotalHeight(struct Node* root)
{
    if (root == NULL)
        return 0;
 
    return getTotalHeight(root->left) +
           getHeight(root) +
           getTotalHeight(root->right);
}
 
// Driver code
int main()
{
    struct Node* root = newNode(1);
 
    root->left = newNode(2);
    root->right = newNode(3);
    root->left->left = newNode(4);
    root->left->right = newNode(5);
    printf("Sum of heights of all Nodes = %d",   
                        getTotalHeight(root));
    return 0;
}

Java




// Java program to find sum of heights of all
// nodes in a binary tree
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;
}
 
/* Compute the "maxHeight" of a particular Node*/
static int getHeight(Node Node)
{
    if (Node == null)
        return 0;
    else {
        /* compute the height of each subtree */
        int lHeight = getHeight(Node.left);
        int rHeight = getHeight(Node.right);
 
        /* use the larger one */
        if (lHeight > rHeight)
            return (lHeight + 1);
        else
            return (rHeight + 1);
    }
}
 
/* Helper function that allocates a new Node with the
given data and NULL left and right pointers. */
static Node newNode(int data)
{
    Node Node = new Node();
    Node.data = data;
    Node.left = null;
    Node.right = null;
 
    return (Node);
}
 
/* Function to sum of heights of individual Nodes
Uses Inorder traversal */
static int getTotalHeight( Node root)
{
    if (root == null)
        return 0;
 
    return getTotalHeight(root.left) + getHeight(root) + getTotalHeight(root.right);
}
 
// Driver code
public static void main(String[] args)
{
    Node root = newNode(1);
 
    root.left = newNode(2);
    root.right = newNode(3);
    root.left.left = newNode(4);
    root.left.right = newNode(5);
    System.out.println("Sum of heights of all Nodes = " + getTotalHeight(root));
}
}

Python3




# Python3 program to find sum of heights
# of all nodes in a binary tree
 
# Helper class that allocates a new Node
# with the given data and None left and
# right pointers.
class newNode:
    def __init__(self, data):
        self.data = data
        self.left = None
        self.right = None
 
# Compute the "maxHeight" of a
# particular Node
def getHeight(Node):
    if (Node == None):
        return 0
    else:
         
        # compute the height of each subtree
        lHeight = getHeight(Node.left)
        rHeight = getHeight(Node.right)
 
        # use the larger one
        if (lHeight > rHeight):
            return (lHeight + 1)
        else:
            return (rHeight + 1)
             
# Function to sum of heights of
# individual Nodes Uses Inorder traversal
def getTotalHeight(root):
    if (root == None):
        return 0
 
    return (getTotalHeight(root.left) +
            getHeight(root) +
            getTotalHeight(root.right))
 
# Driver code
if __name__ == '__main__':
    root = newNode(1)
 
    root.left = newNode(2)
    root.right = newNode(3)
    root.left.left = newNode(4)
    root.left.right = newNode(5)
print("Sum of heights of all Nodes =",
                 getTotalHeight(root))
 
# This code is contributed by PranchalK

C#




// C# program to find sum of heights of all
// nodes in a binary tree
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;
}
 
/* Compute the "maxHeight" of a particular Node*/
static int getHeight(Node Node)
{
    if (Node == null)
        return 0;
    else
    {
        /* compute the height of each subtree */
        int lHeight = getHeight(Node.left);
        int rHeight = getHeight(Node.right);
 
        /* use the larger one */
        if (lHeight > rHeight)
            return (lHeight + 1);
        else
            return (rHeight + 1);
    }
}
 
/* Helper function that allocates a new Node with the
given data and NULL left and right pointers. */
static Node newNode(int data)
{
    Node Node = new Node();
    Node.data = data;
    Node.left = null;
    Node.right = null;
 
    return (Node);
}
 
/* Function to sum of heights of individual Nodes
Uses Inorder traversal */
static int getTotalHeight( Node root)
{
    if (root == null)
        return 0;
 
    return getTotalHeight(root.left) +
                    getHeight(root) +
                    getTotalHeight(root.right);
}
 
// Driver code
public static void Main(String []args)
{
    Node root = newNode(1);
 
    root.left = newNode(2);
    root.right = newNode(3);
    root.left.left = newNode(4);
    root.left.right = newNode(5);
    Console.Write("Sum of heights of all Nodes = " + getTotalHeight(root));
}
}
 
// This code is contributed by Arnab Kundu

Javascript




<script>
// Javascript program to find sum of heights of all
// nodes in a binary tree
 
/* A binary tree Node has data, pointer to
left child and a pointer to right child */
class Node
{
    constructor(data)
    {
        this.data=data;
        this.left=this.right=null;
    }
}
 
/* Compute the "maxHeight" of a particular Node*/
function getHeight(Node)
{
    if (Node == null)
        return 0;
    else {
        /* compute the height of each subtree */
        let lHeight = getHeight(Node.left);
        let rHeight = getHeight(Node.right);
  
        /* use the larger one */
        if (lHeight > rHeight)
            return (lHeight + 1);
        else
            return (rHeight + 1);
    }
}
 
/* Function to sum of heights of individual Nodes
Uses Inorder traversal */
function getTotalHeight(root)
{
    if (root == null)
        return 0;
  
    return getTotalHeight(root.left) + getHeight(root) + getTotalHeight(root.right);
}
 
// Driver code
let root = new Node(1);
 
root.left = new Node(2);
root.right = new Node(3);
root.left.left = new Node(4);
root.left.right = new Node(5);
document.write("Sum of heights of all Nodes = " + getTotalHeight(root));
 
 
// This code is contributed by patel2127
</script>
Output: 
Sum of heights of all Nodes = 8

 

Time Complexity: O(nh) where n is the total number of nodes and h is the height of the binary tree.

Efficient Solution:

The idea is to compute heights and sum them up in the same recursive call.

C++




// C++ program to find sum of heights of all
// nodes in a binary tree
#include <bits/stdc++.h>
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;
};
 
/* Helper function that allocates a new Node with the
   given data and NULL left and right pointers. */
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 sum of heights of individual Nodes
   Uses Inorder traversal */
int getTotalHeightUtil(struct Node* root, int &sum)
{
    if (root == NULL)
        return 0;
 
    int lh = getTotalHeightUtil(root->left, sum);
    int rh = getTotalHeightUtil(root->right, sum);
    int h = max(lh, rh) + 1;
 
    sum = sum + h;
    return h;
}
 
int getTotalHeight(Node *root)
{
    int sum = 0;
    getTotalHeightUtil(root, sum);
    return sum;
}
 
// Driver code
int main()
{
    struct Node* root = newNode(1);
 
    root->left = newNode(2);
    root->right = newNode(3);
    root->left->left = newNode(4);
    root->left->right = newNode(5);
    printf("Sum of heights of all Nodes = %d",   
                        getTotalHeight(root));
    return 0;
}

Java




// Java program to find sum of heights of all
// nodes in a binary tree
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;
    };
    static int sum;
 
    /* Helper function that allocates a new Node with the
    given data and null left and right pointers. */
    static Node newNode(int data)
    {
        Node Node = new Node();
        Node.data = data;
        Node.left = null;
        Node.right = null;
 
        return (Node);
    }
 
    /* Function to sum of heights of individual Nodes
    Uses Inorder traversal */
    static int getTotalHeightUtil(Node root)
    {
        if (root == null)
        {
            return 0;
        }
 
        int lh = getTotalHeightUtil(root.left);
        int rh = getTotalHeightUtil(root.right);
        int h = Math.max(lh, rh) + 1;
 
        sum = sum + h;
        return h;
    }
 
    static int getTotalHeight(Node root)
    {
        sum = 0;
        getTotalHeightUtil(root);
        return sum;
    }
 
    // Driver code
    public static void main(String[] args)
    {
        Node root = newNode(1);
 
        root.left = newNode(2);
        root.right = newNode(3);
        root.left.left = newNode(4);
        root.left.right = newNode(5);
        System.out.printf("Sum of heights of all Nodes = %d",
                                       getTotalHeight(root));
    }
}
 
// This code is contributed by PrinciRaj1992

Python3




# Python3 program to find sum of heights
# of all nodes in a binary tree
 
# A binary tree Node has data, pointer to
# left child and a pointer to right child
class Node:
     
    def __init__(self, key):
         
        self.data = key
        self.left = None
        self.right = None
 
sum = 0
 
# Function to sum of heights of individual
# Nodes Uses Inorder traversal
def getTotalHeightUtil(root):
     
    global sum
     
    if (root == None):
        return 0
 
    lh = getTotalHeightUtil(root.left)
    rh = getTotalHeightUtil(root.right)
    h = max(lh, rh) + 1
 
    sum = sum + h
    return h
 
def getTotalHeight(root):
     
    getTotalHeightUtil(root)
     
    return sum
 
# Driver code
if __name__ == '__main__':
     
    root = Node(1)
    root.left = Node(2)
    root.right = Node(3)
    root.left.left = Node(4)
    root.left.right = Node(5)
     
    print("Sum of heights of all Nodes =",
           getTotalHeight(root))
 
# This code is contributed by mohit kumar 29

C#




// C# program to find sum of heights of
// all nodes in a binary tree
using System;
using System.Collections.Generic;
     
class GFG
{
 
    /* A binary tree Node has data, pointer to
    left child and a pointer to right child */
    class Node
    {
        public int data;
        public Node left;
        public Node right;
    };
    static int sum;
 
    /* Helper function that allocates
    a new Node with the given data and
    null left and right pointers. */
    static Node newNode(int data)
    {
        Node Node = new Node();
        Node.data = data;
        Node.left = null;
        Node.right = null;
 
        return (Node);
    }
 
    /* Function to sum of heights of
    individual Nodes Uses Inorder traversal */
    static int getTotalHeightUtil(Node root)
    {
        if (root == null)
        {
            return 0;
        }
 
        int lh = getTotalHeightUtil(root.left);
        int rh = getTotalHeightUtil(root.right);
        int h = Math.Max(lh, rh) + 1;
 
        sum = sum + h;
        return h;
    }
 
    static int getTotalHeight(Node root)
    {
        sum = 0;
        getTotalHeightUtil(root);
        return sum;
    }
 
    // Driver code
    public static void Main(String[] args)
    {
        Node root = newNode(1);
 
        root.left = newNode(2);
        root.right = newNode(3);
        root.left.left = newNode(4);
        root.left.right = newNode(5);
        Console.Write("Sum of heights of all Nodes = {0}",
                                    getTotalHeight(root));
    }
}
 
// This code is contributed by Princi Singh

Javascript




<script>
 
// JavaScript program to find sum of heights of all
// nodes in a binary tree
 
/* A binary tree Node has data, pointer to
    left child and a pointer to right child */
class Node
{
    constructor(data)
    {
        this.data=data;
        this.left=this.right=null;
    }
}
 
let sum;
/* Function to sum of heights of individual Nodes
    Uses Inorder traversal */
function  getTotalHeightUtil(root)
{
    if (root == null)
        {
            return 0;
        }
  
        let lh = getTotalHeightUtil(root.left);
        let rh = getTotalHeightUtil(root.right);
        let h = Math.max(lh, rh) + 1;
  
        sum = sum + h;
        return h;
}
 
function getTotalHeight(root)
{
    sum = 0;
        getTotalHeightUtil(root);
        return sum;
}
 
// Driver code
let root = new Node(1);
 
root.left = new Node(2);
root.right = new Node(3);
root.left.left = new Node(4);
root.left.right = new Node(5);
document.write("Sum of heights of all Nodes = ",
                  getTotalHeight(root));
     
     
// This code is contributed by unknown2108
 
</script>
 
    
Output: 
Sum of heights of all Nodes = 8

 

Time Complexity: O(n) where n is the total number of nodes of the binary tree.
 

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