https://codeperfectplus.com/diagonal-difference-problem-solving-hackerrank

diagonal-difference-problem-solving-hackerrank.cpp

#include <bits/stdc++.h>

using namespace std;

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

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); 
}