本题通过提前统计i行 j列 减少两层for

#include<bits/stdc++.h>
using namespace std;
short a[1005][1005],x[1005],y[1005];long long ans = -11451451451,sum;
int main(void){
    freopen("laser.in", "r", stdin);    freopen("laser.out", "w", stdout);
    int n;cin >>n;
    for(int i = 1;i <= n;i++){
    	for(int j = 1;j <= n;j++){
    		scanf("%d",&a[i][j]);
    		y[i] += a[i][j];
    		x[j] += a[i][j];
		}
	}
	for(int i = 1;i <= n;i++){
		for(int j = 1;j <= n;j++){
			if(a[i][j] == 0){
				sum = x[j]+y[i];
				ans = max(ans,sum);
			}
		}
	}
	printf("%lld",ans); 
	return 0;
}