leetcode

0 class Solution {

1 public:

2 int diagonalSum(vector<vector<int>> &mat) {

3 int n = mat.size(), sum = 0;

4 for (int i = 0; i < n; i++)

5 sum += mat[i][i] + mat[i][n - i - 1];

6

7 if (n % 2) sum -= mat[n / 2][n / 2];

8 return sum;

9 }

10 };