学步园

http://acm.hdu.edu.cn/showproblem.php?pid=2159

二维完全背包，限定因素是容量和物品总个数，内层循环顺序，

#include <stdio.h>
#include <string.h>
#include <algorithm>
using namespace std;
const int INF = 0x3f3f3f3f;
int dp[110][110];

int main()
{
	int n,m,k,s;
	int c[110],w[110];
	while(~scanf("%d %d %d %d",&n,&m,&k,&s))
	{
		for(int i = 1; i <= k; i++)
			scanf("%d %d",&w[i],&c[i]);

		for(int i = 0; i <= m; i++)
		{
			for(int j = 0; j <= s; j++)
			{
				if(j == 0)
					dp[i][j] = 0;
				else dp[i][j] = -INF;
			}
		}

		for(int i = 1; i <= k; i++)
		{
			for(int j = c[i]; j <= m; j++)
			{
				for(int g = 1; g <= s; g++)
				{
					dp[j][g] = max(dp[j][g], dp[j-c[i]][g-1]+w[i]);
				}
			}
		}
		int f = 0;
		for(int i = 0; i <= m; i++)
		{
			for(int j = 0; j <= s; j++)
			{
				if(dp[i][j] >= n)
				{
					printf("%d\n",m-i);
					f = 1;
					break;
				}
			}
			if(f == 1) break;
		}
		if(!f) printf("-1\n");
	}
	return 0;
}