poj 1609 Tiling Up Blocks dp入门之记忆化搜索

//poj 1609
//sep9
#include <iostream>
using namespace std;
const int max_p=128;
int n;
int num[max_p][max_p];
int dp[max_p][max_p];

int search(int x,int y)
{
	if(dp[x][y])
		return dp[x][y];	
	int i,j,maxx=0;
	for(i=1;i<=x;++i)
		for(j=1;j<=y;++j)
			if(!(i==x&&j==y))
				if(num[i][j])
					maxx=max(maxx,search(i,j));
	return dp[x][y]=maxx+num[x][y];
}		

int main()
{
	while(scanf("%d",&n)==1){
		if(n==0){
			printf("*\n");
			break;
		}
		int max_l=0,max_m=0;
		memset(num,0,sizeof(num));
		memset(dp,0,sizeof(dp));
		for(int i=0;i<n;++i){
			int a,b;
			scanf("%d%d",&a,&b);
			++num[a][b];
			max_l=max(max_l,a);
			max_m=max(max_m,b);
		}
		int i,j,ans=0;
		for(i=1;i<=max_l;++i)
			for(j=1;j<=max_m;++j)
				if(num[i][j])
					ans=max(ans,search(i,j));
		printf("%d\n",ans);
	}
	return 0;	
}