poj 1609 dp

题目链接：http://poj.org/problem?id=1609

#include <cstdio>
#include <cstring>
#include <iostream>
#include <cmath>
#include <algorithm>
#include <queue>
#include <vector>
using namespace std;

const int maxe = 50000;
const int maxn = 105;
const int INF  = 0x3f3f3f;


int main()
{
    //freopen("E:\\acm\\input.txt","r",stdin);
    int N;
    int dp[maxn][maxn];
    int B[maxn][maxn];
    int Maxl,Maxm;
    while(cin>>N){
        memset(dp,0,sizeof(dp));  //dp[i][j]表示最大的l为i，m为j的高度
        memset(B,0,sizeof(B));
        Maxl = 0, Maxm = 0;

        if(N == 0)  {  printf("*\n");  break;   }
        for(int i=1;i<=N;i++){
            int a,b;
            scanf("%d %d",&a,&b);
            Maxl = max(Maxl,a);
            Maxm = max(Maxm,b);
            B[a][b]++;
        }
        int ans = 0;
        for(int i=1;i<=Maxl;i++)
          for(int j=1;j<=Maxm;j++){
             dp[i][j] = B[i][j] + max(dp[i-1][j] , dp[i][j-1] );
             if(B[i][j])  ans = max(ans,dp[i][j]);
        }
        printf("%d\n",ans);
    }
}