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###### tags: `Leetcode`

# 1572. Matrix Diagonal Sum

## 題目
###### Link : https://leetcode.com/problems/matrix-diagonal-sum/

## 程式碼

class Solution {
public:
    int diagonalSum(vector<vector<int>>& mat) {
        const int n = mat.size();
        int ans = 0;
        for(int i = 0, j = n - 1;i < n;++i, --j){
            ans += mat[i][i];
            ans += mat[i][j];
        }
        if(n & 1)
            ans -= mat[n >> 1][n >> 1];
        return ans;
    }
};