poj 2029 Get Many Persimmon Trees 各种解法都有，其实就是瞎搞不算吧是dp

连接：http://poj.org/problem?id=2029

题意：给你一个map，然后在上面种树，问你h*w的矩形上最多有几棵树~这题直接搜就可以。不能算是DP

用树状数组也可作。

#include <stdio.h>
#include <string.h>
#include <iostream>
#include <algorithm>
#include <stdlib.h>
#include <vector>
#include <set>
#include <queue>
#include <stack>
#define loop(s,i,n) for(i = s;i < n;i++)
#define cl(a,b) memset(a,b,sizeof(a))
using namespace std;
const int MAX = 155;
int map[MAX][MAX];
int dp[MAX][MAX];

int main(){
    int n, i, j, ii, jj;
    int W, H, w, h;
    while(cin >> n && n){
        memset(map, 0, sizeof(map));
        memset(dp, 0, sizeof(dp));
        cin >> W >> H;
        while(n --){
            int x, y;
            cin >> x >> y;
            map[y][x] = 1;
        }
        cin >> w >> h;
        for(i = 1; i <= H; i ++)
            for(j = 1; j <= W; j ++)
                dp[i][j] = dp[i-1][j] + dp[i][j-1] - dp[i-1][j-1] + map[i][j];
        int ans = 0;
        for(i = 1; i <= H; i ++)
            for(j = 1; j <= W; j ++){
                ii = i - h + 1;
                jj = j - w + 1;
                if(ii < 1 || jj < 1) continue;
                ans = max(ans, dp[i][j] - dp[ii-1][j] - dp[i][jj-1] + dp[ii-1][jj-1]);
            }
        cout << ans << endl;
    }
    return 0;
}