CSP 邻域均值 二维前缀和

#include <iostream>
#include <vector>
#include<algorithm>

using namespace std;


const int N = 6100; // 开610会卡90分

int n,l,r,t;
int a[N][N];
int s[N][N];

int tmp;
int sum;

int main()
{
    cin >> n >> l >> r >> t;
    for(int i=0;i < n;i++)
    {
        for(int j=0;j < n;j++)
        {
            cin >> tmp;
            a[i][j] = tmp - t;
            s[i][j] = s[i-1][j] + s[i][j-1] -s[i-1][j-1] + a[i][j];
        }
    }


    int x;
    for(int i=0;i < n;i++)
    {
        for(int j=0;j < n;j++)
        {
            //if()
            int x1 = max(0,i-r),y1 = max(0,j-r);
            int x2 = min(i+r,n-1),y2 = min(j+r,n-1);
            x = s[x2][y2] - s[x1-1][y2] - s[x2][y1-1] + s[x1-1][y1-1];
            if(x <= 0)   sum++;
        }
    }


    cout << sum;

    return 0;
}