P2004 领地选择 29分求帮助

#include<bits/stdc++.h>
using namespace std;
long long a[1009][1009];
long long s[1009][1009];
int main(){
	long long n,k,g,ansx,ansy;
	cin>>n>>k>>g;
	s[0][0]=0;
	for(int i = 1;i<=n;i++){
		for(int j = 1;j<=k;j++){
			cin>>a[i][j];
			s[i][j]=a[i][j]+s[i-1][j]+s[i][j-1]-s[i-1][j-1];
		}
	}
	long long m=-1;
	for(int x1 = 1;x1<=n-g;x1++){
		for(int y1 = 1;y1<=k-g;y1++){
			//if(x1+g>n||y1+g>k) continue;
			long long x2=x1+g;
			long long y2=y1+g;
			long long cnt;
			cnt = s[x2][y2]-s[x1-1][y2]-s[x2][y1-1]+s[x1-1][y1-1];
			if(cnt>m){
				m=cnt;
				ansx=x1;
				ansy=y1;
			}
		}
	}
	cout<<ansx<<" "<<ansy;
}