poj 3628 Bookshelf 2

http://poj.org/problem?id=3628

01背包

 #include <cstdio>
 #include <iostream>
 #include <cstring>
 #include <algorithm>
 #define maxn 21
 #define ll long long
 using namespace std;

 ll h[maxn];
 int n;
 ll b;
 ll dp[];
 ll max1(ll a,ll b)
 {
     return a>b?a:b;
 }

 int main()
 {
     while(scanf("%d%lld",&n,&b)!=EOF)
     {
         ll v=;
         for(int i=; i<=n; i++)
         {
             scanf("%lld",&h[i]);
             v+=h[i];
         }
         for(int i=; i<=n; i++)
         {
             for(ll j=v; j>=h[i]; j--)
             {
                 dp[j]=max(dp[j-h[i]]+h[i],dp[j]);
             }
         }
         for(ll j=; j<=v; j++)
         {
             if(dp[j]>=b)
             {
               printf("%lld\n",dp[j]-b);
               break;
             }
         }
     }
     return ;
 }