hdu 1559 暴力

这数据量和这时限，很显然暴力是最好的解法，预处理前缀和，n方复杂度秒过。

#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;

const int N = 1001;
int a[N][N];
int m, n, x, y;

int get( int i, int j )
{
    int x1 = a[i + x - 1][j + y - 1];
    int x2 = a[i + x - 1][j - 1];
    int x3 = a[i - 1][j + y - 1];
    int x4 = a[i - 1][j - 1];
    return x1 - x2 - x3 + x4;
}

int main ()
{
    int t;
    scanf("%d", &t);
    while ( t-- )
    {
        scanf("%d%d%d%d", &m, &n, &x, &y);
        for ( int i = 1; i <= m; i++ )
            for ( int j = 1; j <= n; j++ )
                scanf("%d", &a[i][j]);
        for ( int i = 1; i <= m; i++ )
            for ( int j = 1; j <= n; j++ )
                a[i][j] += a[i][j - 1];
        for ( int i = 1; i <= m; i++ )
            for ( int j = 1; j <= n; j++ )
                a[i][j] += a[i - 1][j];
        int ans = -999999999;
        for ( int i = 1; i + x - 1 <= m; i++ )
            for ( int j = 1; j + y - 1 <= n; j++ )
                ans = max( ans, get( i, j ) );
        printf("%d
", ans);
    }
    return 0;
}