Matrix Diagonal Sum LeetCode solution in Java

1
class Solution {
2
  public int diagonalSum(int[][] mat) {
3
    int sum1 = 0;
4
    int sum2 = 0;
5
    int n = mat.length;
6
    for (int i = 0; i < n; i++) {
7
      sum1 += mat[i][i];
8
      sum2 += mat[i][n - i - 1];
9
    }
10
    int res = sum1 + sum2;
11
    if (n % 2 != 0) {
12
      res -= mat[n / 2][n / 2];
13
    }
14
    return res;
15
  }
16
}