diagonal_difference.cpp

int diagonalDifference(vector<vector<int>> arr) {
    int  lDiagSum = 0, rDiagSum = 0;
    uint i, j, size = arr[0].size();
    for(i = 0, j = size - 1;
        (i < size && j >= 0);
        i++, j--){
        lDiagSum += arr[i][i];
        rDiagSum += arr[i][j];
    }
    return abs(lDiagSum - rDiagSum);
}