# Diagonal Difference | HackerRank Solution

Hello coders, today we are going to solve Diagonal Difference HackerRank Solution which is a Part of HackerRank Algorithms Series.

Given a square matrix, calculate the absolute difference between the sums of its diagonals.

For example, the square matrixÂ arrÂ is shown below:

``````1 2 3
4 5 6
9 8 9  ``````

The left-to-right diagonal =Â 1 + 5 +9 = 15. The right to left diagonal =Â 3 + 5 + 9 = 17. Their absolute difference isÂ |15 – 17| = 2.

Function description

Complete theÂ DiagonalDifferenceÂ function in the editor below.

diagonalDifference takes the following parameter:

• int arr[n][m]: an array of integers

Return

• int: the absolute diagonal difference

## Input Format

The first line contains a single integer,Â n, the number of rows and columns in the square matrixÂ arr.
Each of the nextÂ nÂ lines describes a row,Â arr[i], and consists ofÂ nÂ space-separated integersÂ arr[i][j].

## Constraints

• -100 <= arr[i][j] <= 100

## Output Format

Return the absolute difference between the sums of the matrix’s two diagonals as a single integer.

Sample Input

``````3
11 2 4
4 5 6
10 8 -12``````

Sample Output

``15``

Explanation

The primary diagonal is:

``````11
5
-12``````

Sum across the primary diagonal: 11 + 5 – 12 = 4

The secondary diagonal is:

``````     4
5
10``````

Sum across the secondary diagonal: 4 + 5 + 10 = 19
Difference: |4 – 19| = 15

Note:Â |x| is theÂ absolute valueÂ of x

## Solution – Diagonal Difference Solution

### C++

```#include <bits/stdc++.h>

using namespace std;

string ltrim(const string &);
string rtrim(const string &);
vector<string> split(const string &);

/*
* Complete the 'diagonalDifference' function below.
*
* The function is expected to return an INTEGER.
* The function accepts 2D_INTEGER_ARRAY arr as parameter.
*/

int diagonalDifference(vector<vector<int>> arr) {

int s1 = 0;
int s2 = 0;
int n = arr.size();

for(int i=0;i<n;i++) {
s1 += arr[i][i];
s2 += arr[i][n-i-1];
}
return abs(s1 - s2);
}

int main()
{
ofstream fout(getenv("OUTPUT_PATH"));

string n_temp;
getline(cin, n_temp);

int n = stoi(ltrim(rtrim(n_temp)));

vector<vector<int>> arr(n);

for (int i = 0; i < n; i++) {
arr[i].resize(n);

string arr_row_temp_temp;
getline(cin, arr_row_temp_temp);

vector<string> arr_row_temp = split(rtrim(arr_row_temp_temp));

for (int j = 0; j < n; j++) {
int arr_row_item = stoi(arr_row_temp[j]);

arr[i][j] = arr_row_item;
}
}

int result = diagonalDifference(arr);

fout << result << "\n";

fout.close();

return 0;
}

string ltrim(const string &str) {
string s(str);

s.erase(
s.begin(),
find_if(s.begin(), s.end(), not1(ptr_fun<int, int>(isspace)))
);

return s;
}

string rtrim(const string &str) {
string s(str);

s.erase(
find_if(s.rbegin(), s.rend(), not1(ptr_fun<int, int>(isspace))).base(),
s.end()
);

return s;
}

vector<string> split(const string &str) {
vector<string> tokens;

string::size_type start = 0;
string::size_type end = 0;

while ((end = str.find(" ", start)) != string::npos) {
tokens.push_back(str.substr(start, end - start));

start = end + 1;
}

tokens.push_back(str.substr(start));

}
```

### Python

```#!/bin/python3

import math
import os
import random
import re
import sys

#
# Complete the 'diagonalDifference' function below.
#
# The function is expected to return an INTEGER.
# The function accepts 2D_INTEGER_ARRAY arr as parameter.
#

def diagonalDifference(arr):
d1 = sum([arr[x][x] for x in range(len(arr))])
d2 = sum([arr[x][n - 1 - x] for x in range(len(arr))])
return(abs(d1 - d2))

if __name__ == '__main__':
fptr = open(os.environ['OUTPUT_PATH'], 'w')

n = int(input().strip())

arr = []

for _ in range(n):
arr.append(list(map(int, input().rstrip().split())))

result = diagonalDifference(arr)

fptr.write(str(result) + '\n')

fptr.close()
```

Disclaimer: The above Problem (Diagonal Difference) is generated by Hacker Rank but the Solution is Provided by CodingBroz. This tutorial is only for Educational and Learning Purpose.

### 1 thought on “Diagonal Difference | HackerRank Solution”

1. Alejandro Vistorte

I found a way that only needs to loop through the matrix once.

def diagonalDifference(arr):
difference = 0
for index, cont in enumerate(arr):
difference += cont[index] – cont[-index – 1]
return abs(difference)