题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=2159
思路:二维完全背包,两个限制条件,忍耐值、怪的数目s;
#include<cstdio>
#include<cstring>
using namespace std;
const int num=105;
int n,m,k,s,dp[num][num];
struct node
{
int val,c;
}d[num];
int max(int a,int b)
{
if(a>b)
return a;
return b;
}
int main()
{
int i,j,p;
//freopen("in.txt","r",stdin);
while(scanf("%d%d%d%d",&n,&m,&k,&s)!=EOF)
{
for(i=0;i<k;i++)
scanf("%d%d",&d[i].val,&d[i].c);
memset(dp,0,sizeof(dp));
for(i=0;i<k;i++)
for(j=1;j<=s;j++)
for(p=d[i].c;p<=m;p++)
dp[j][p]=max(dp[j][p],dp[j-1][p-d[i].c]+d[i].val);
for(i=0;i<=m;i++)
if(dp[s][i]>=n)
break;
if(i>m)
printf("-1\n");
else
printf("%d\n",m-i);
}
return 0;
}