# Difference between sum of even and odd valued nodes in a Binary Tree

Given a binary tree, the task is to find the absolute difference between the even valued and the odd valued nodes in a binary tree.
Examples:

```Input:
5
/   \
2     6
/  \     \
1    4     8
/     / \
3     7   9
Output: 5
Explanation:
Sum of the odd value nodes is:
5 + 1 + 3 + 7 + 9 = 25
Sum of the even value nodes is:
2 + 6 + 4 + 8 = 20
Absolute difference = (25 – 20) = 5.

Input:
4
/   \
1     4
/  \     \
7    2     6
Output: 8

```

Approach:
Follow the steps below to solve the problem:

• Traverse each node in the tree and check if the value at that node is odd or even.
• Update oddSum and evenSum accordingly after visiting each node.
• After complete traversal of the tree, print the absolute difference between oddSum and evenSum.

Below is the implementation of the above approach:

## C++

 `// C++ implementation of ` `// the above approach ` `#include ` `using` `namespace` `std; ` ` `  `int` `oddsum = 0; ` `int` `evensum = 0; ` `int` `ans = 0; ` ` `  `struct` `node { ` `    ``int` `data; ` `    ``struct` `node* left; ` `    ``struct` `node* right; ` `}; ` ` `  `struct` `node* newnode(``int` `data) ` `{ ` `    ``node* temp = ``new` `node(); ` `    ``temp->data = data; ` `    ``temp->left = temp->right = NULL; ` `    ``return` `temp; ` `} ` ` `  `// Function calculate the sum of ` `// odd and even value node ` `void` `OddEvenDifference(``struct` `node* ` `                           ``root) ` `{ ` `    ``// If root is NULL ` `    ``if` `(root == NULL) { ` `        ``return``; ` `    ``} ` `    ``else` `{ ` `        ``// Check if current root ` `        ``// is odd or even ` `        ``if` `(root->data % 2 == 0) { ` `            ``evensum += root->data; ` `        ``} ` `        ``else` `{ ` `            ``oddsum += root->data; ` `        ``} ` `        ``// Call on the left subtree ` `        ``OddEvenDifference(root->left); ` ` `  `        ``// Call on the right subtree ` `        ``OddEvenDifference(root->right); ` `    ``} ` `} ` ` `  `// Driver Code ` `int` `main() ` `{ ` `    ``node* root = newnode(5); ` `    ``root->left = newnode(2); ` `    ``root->right = newnode(6); ` `    ``root->left->left = newnode(1); ` `    ``root->left->right = newnode(4); ` `    ``root->left->right->left ` `        ``= newnode(3); ` `    ``root->right->right = newnode(8); ` `    ``root->right->right->right ` `        ``= newnode(9); ` `    ``root->right->right->left ` `        ``= newnode(7); ` ` `  `    ``OddEvenDifference(root); ` ` `  `    ``cout << ``abs``(oddsum - evensum) ` `         ``<< endl; ` `} `

## Java

 `// Java implementation of ` `// the above approach ` `class` `GFG{ ` ` `  `static` `int` `oddsum = ``0``; ` `static` `int` `evensum = ``0``; ` `static` `int` `ans = ``0``; ` ` `  `static` `class` `node ` `{ ` `    ``int` `data; ` `    ``node left; ` `    ``node right; ` `}; ` ` `  `static` `node newnode(``int` `data) ` `{ ` `    ``node temp = ``new` `node(); ` `    ``temp.data = data; ` `    ``temp.left = temp.right = ``null``; ` `    ``return` `temp; ` `} ` ` `  `// Function calculate the sum of ` `// odd and even value node ` `static` `void` `OddEvenDifference(node root) ` `{ ` `     `  `    ``// If root is null ` `    ``if` `(root == ``null``)  ` `    ``{ ` `        ``return``; ` `    ``} ` `    ``else`  `    ``{ ` `         `  `        ``// Check if current root ` `        ``// is odd or even ` `        ``if` `(root.data % ``2` `== ``0``)  ` `        ``{ ` `            ``evensum += root.data; ` `        ``} ` `        ``else`  `        ``{ ` `            ``oddsum += root.data; ` `        ``} ` `         `  `        ``// Call on the left subtree ` `        ``OddEvenDifference(root.left); ` ` `  `        ``// Call on the right subtree ` `        ``OddEvenDifference(root.right); ` `    ``} ` `} ` ` `  `// Driver Code ` `public` `static` `void` `main(String[] args) ` `{ ` `    ``node root = newnode(``5``); ` `    ``root.left = newnode(``2``); ` `    ``root.right = newnode(``6``); ` `    ``root.left.left = newnode(``1``); ` `    ``root.left.right = newnode(``4``); ` `    ``root.left.right.left = newnode(``3``); ` `    ``root.right.right = newnode(``8``); ` `    ``root.right.right.right = newnode(``9``); ` `    ``root.right.right.left = newnode(``7``); ` ` `  `    ``OddEvenDifference(root); ` ` `  `    ``System.out.print(Math.abs( ` `        ``oddsum - evensum) + ``"\n"``); ` `} ` `} ` ` `  `// This code is contributed by amal kumar choubey `

## C#

 `// C# implementation of ` `// the above approach ` `using` `System; ` ` `  `class` `GFG{ ` ` `  `static` `int` `oddsum = 0; ` `static` `int` `evensum = 0; ` `//static int ans = 0; ` ` `  `class` `node ` `{ ` `    ``public` `int` `data; ` `    ``public` `node left; ` `    ``public` `node right; ` `}; ` ` `  `static` `node newnode(``int` `data) ` `{ ` `    ``node temp = ``new` `node(); ` `    ``temp.data = data; ` `    ``temp.left = temp.right = ``null``; ` `    ``return` `temp; ` `} ` ` `  `// Function calculate the sum of ` `// odd and even value node ` `static` `void` `OddEvenDifference(node root) ` `{ ` `     `  `    ``// If root is null ` `    ``if` `(root == ``null``)  ` `    ``{ ` `        ``return``; ` `    ``} ` `    ``else` `    ``{ ` `         `  `        ``// Check if current root ` `        ``// is odd or even ` `        ``if` `(root.data % 2 == 0)  ` `        ``{ ` `            ``evensum += root.data; ` `        ``} ` `        ``else` `        ``{ ` `            ``oddsum += root.data; ` `        ``} ` `         `  `        ``// Call on the left subtree ` `        ``OddEvenDifference(root.left); ` ` `  `        ``// Call on the right subtree ` `        ``OddEvenDifference(root.right); ` `    ``} ` `} ` ` `  `// Driver Code ` `public` `static` `void` `Main(String[] args) ` `{ ` `    ``node root = newnode(5); ` `    ``root.left = newnode(2); ` `    ``root.right = newnode(6); ` `    ``root.left.left = newnode(1); ` `    ``root.left.right = newnode(4); ` `    ``root.left.right.left = newnode(3); ` `    ``root.right.right = newnode(8); ` `    ``root.right.right.right = newnode(9); ` `    ``root.right.right.left = newnode(7); ` ` `  `    ``OddEvenDifference(root); ` ` `  `    ``Console.Write(Math.Abs( ` `        ``oddsum - evensum) + ``"\n"``); ` `} ` `} ` ` `  `// This code is contributed by amal kumar choubey `

Output:

```5
```

Time Complexity: O(N)
Auxiliary Space: O(1)

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Improved By : Amal Kumar Choubey