题目：http://acm.hdu.edu.cn/showproblem.php?pid=1559
1 #include <cstring> 2 #include <cstdlib> 3 #include <cstdio> 4 #include <iostream> 5 #include <algorithm> 6 using namespace std; 7 const int maxn = 1000+10; 8 const int INF = 1<<28; 9 int map[maxn][maxn]; //表示以[1,1]为左上角，以[i,j]为右下角的矩形的和 10 11 int main() 12 { 13 int t, i, j, m, n, x, y; 14 int s1, sc, Max, ans; 15 scanf("%d", &t); 16 while(t--) 17 { 18 memset(map, 0, sizeof(map)); 19 Max = -INF; 20 scanf("%d%d%d%d", &m, &n, &x, &y); 21 for(i = 1; i <= m; i++) 22 { 23 s1 = 0; 24 for(j = 1; j <= n; j++) 25 { 26 scanf("%d", &sc); 27 s1 += sc; 28 map[i][j] = s1+map[i-1][j]; 29 } 30 } 31 for(i = 1; i <= m; i++) 32 for(j = 1; j <= n; j++) 33 if((i+x-1)<=m && (j+y-1)<=n) 34 { 35 ans = map[i+x-1][j+y-1]-map[i+x-1][j-1]-map[i-1][j+y-1]+map[i-1][j-1];//减出来就是以[i,j] 36 //为左顶点，大小为xy的矩形的和 37 if(Max < ans) 38 Max = ans; 39 } 40 printf("%d ", Max); 41 } 42 return 0; 43 }