This tutorial provides Java and Python solution to diagonal difference problem of Hackerrank.

Hackerrank Challenge Details

Problem Statement:

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

Input Format:

The first line contains a single integer, N. The next N lines denote the matrix's rows, with each line containing N space-separated integers describing the columns.

Output Format:

Print the absolute difference between the two sums of the matrix's 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

Solution Details

Java Implementation:

package com.saintech.allprogtutorials.hackerrank.algos;

import java.util.Scanner;

/**
 * @author Sain Technology Solutions
 *
 * Solution to Problem - https://www.hackerrank.com/challenges/diagonal-difference
 */
public class DiagonalDifference {
	
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		final int N = Integer.parseInt(in.nextLine());
		long diff = 0;
		for(int i=0; i < N; i++) {
			String[] row = in.nextLine().split(" ");
			diff += (Integer.parseInt(row[i]) - Integer.parseInt(row[N - 1 - i]));
		}
		
		System.out.println(Math.abs(diff));
		
		in.close();
	}
}

Python Implementation: 

#!/bin/python

import sys


N = int(raw_input())
difference = 0
for i in xrange(N):
    row = raw_input().split()
    difference += (int(row[i]) - int(row[N-1-i]))
print abs(difference)

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