SoL：完全背包。。。

#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>

using namespace std;

const int INF = 0x3f3f3f3f;
const int maxm = 10000 + 10;
const int maxn = 50 + 10;

int dp[maxm];
int value[maxn];//每袋的价格
int weight[maxn];//每袋的重量

int nValue,nKind;
//完全背包，代价为cost,获得的价值为weight
void CompletePack(int cost,int weight)
{
    for(int i=cost;i<=nValue;i++)
      dp[i]=min(dp[i],dp[i-cost]+weight);
}

int main()
{
    while(~scanf("%d%d",&nValue,&nKind))
    {
        for(int i=0;i<nKind;i++)
			scanf("%d%d",&weight[i],&value[i]);
		for(int i=0;i<=nValue;i++)
			dp[i]=INF;
		dp[0]=0;
        for(int i=0;i<nKind;i++)
          CompletePack(value[i],weight[i]);
        if(dp[nValue]>=INF)
        	printf("-1\n");
        else 
			printf("%d\n",dp[nValue]);
    }
    return 0;
}

hrbust 1993 数硬币