Interview Question & Answer – 6

Question

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

For example, the square matrix is shown below:

1 2 3
4 5 6
9 8 9

Ans : | (1+5+9) – (3+5+9) | = 2.

Solution

static int diagonalDifference(int[][] arr) {
    int diagonalSum1 = 0;
    int diagonalSum2 = 0;
    int length = arr.length;
    for (int row = 0; row < length; row++){
        diagonalSum1 += arr[row][row];
        diagonalSum2 += arr[row][length - row - 1];
    }
    return Math.abs(diagonalSum1 - diagonalSum2);
}