poj 2029 Get Many Persimmon Trees

http://poj.org/problem?id=2029

 1 #include <cstdio>

 2 #include <cstring>

 3 #include <algorithm>

 4 #define maxn 200

 5 using namespace std;

 6 

 7 int dp[maxn][maxn];

 8 int n,s,t,w,h;

 9 int a[maxn][maxn];

10 

11 int main()

12 {

13     while(scanf("%d",&n)!=EOF)

14     {

15         if(n==0) break;

16         scanf("%d%d",&w,&h);

17         memset(dp,0,sizeof(dp));

18         memset(a,0,sizeof(a));

19         for(int i=1; i<=n; i++)

20         {

21             int x,y;

22             scanf("%d%d",&x,&y);

23             a[x][y]=1;

24         }

25         scanf("%d%d",&s,&t);

26         for(int i=1; i<=w; i++)

27         {

28             for(int j=1; j<=h; j++)

29             {

30                 dp[i][j]=dp[i-1][j]+dp[i][j-1]-dp[i-1][j-1]+a[i][j];

31             }

32         }

33         int ans=-1;

34         for(int i=1; i<=w; i++)

35         {

36             for(int j=1; j<=h; j++)

37             {

38                 int x1=i-s+1;

39                 int y1=j-t+1;

40                 if(x1<1||y1<1) continue;

41                 ans=max(ans,dp[i][j]-dp[x1-1][j]-dp[i][y1-1]+dp[x1-1][y1-1]);

42             }

43         }

44         printf("%d\n",ans);

45     }

46     return 0;

47 }

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