python/TangDou/XiTi/1080.cpp

#include <bits/stdc++.h>

using namespace std;

int main() {
    int m, n;
    cin >> m >> n;
    int a[100][100] = {0};
    for (int i = 0; i < m; ++i) {
        for (int j = 0; j < n; ++j) {
            cin >> a[i][j];
        }
    }
    int sum = 0;
    for (int i = 0; i < m; ++i) {
        sum += a[i][0] + a[i][n - 1]; //左+右
    }

    for (int i = 1; i < n - 1; ++i) {
        sum += a[0][i] + a[m - 1][i];//上+下
    }
    cout << sum << endl;
    return 0;
}