题解

#include <bits/stdc++.h>
using namespace std;
int a[1010][1010];
int main(){
    int n,m;
    cin >> n >> m;
    for(int i = 1;i <= n;i++){
        for(int j = 1;j <= m;j++){
            cin >> a[i][j];
        }
    }
    int maxSum = -2000000000;
    for(int k = (1 - m);k <= (n - 1);k++){
        int sum = 0;
        for(int i = 1;i <= n;i++){
            int j = i - k;
            if(j >= 1 && j <= m){
                sum += a[i][j];
            }
        }
        maxSum = max(maxSum,sum);
    }
    cout << maxSum;
    return 0;
}