题解

#include <iostream>
#include <vector>
#include <climits>
using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int m, n;
    cin >> m >> n;
    vector<vector<int>> mat(m, vector<int>(n));
    vector<long long> row_sum(m, 0);  // 每行的总和
    vector<long long> col_sum(n, 0);  // 每列的总和

    // 输入矩阵并计算行总和
    for (int i = 0; i < m; ++i) {
        long long sum = 0;
        for (int j = 0; j < n; ++j) {
            cin >> mat[i][j];
            sum += mat[i][j];
        }
        row_sum[i] = sum;
    }

    // 计算列总和
    for (int j = 0; j < n; ++j) {
        long long sum = 0;
        for (int i = 0; i < m; ++i) {
            sum += mat[i][j];
        }
        col_sum[j] = sum;
    }

    // 遍历每个中心点，计算十字能量和
    long long max_energy = 0;
    for (int i = 0; i < m; ++i) {
        for (int j = 0; j < n; ++j) {
            long long current = row_sum[i] + col_sum[j] - mat[i][j];
            if (current > max_energy) {
                max_energy = current;
            }
        }
    }

    cout << max_energy << endl;
    return 0;
}