hdu2546 饭卡 ０１背包

link:http://acm.hdu.edu.cn/showproblem.php?pid=2546

也算一个贪心的想法吧．

先把总钱数减去５，再把价值最大的挑出来．然后用０１背包．最终买下挑出来的那个价值最大的商品．这样的话，我就实现了最终用最少的钱数买了价值最多的商品，剩下钱数当然也是最少了．

 #include <iostream>
 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
 #include <cmath>
 #include <cctype>
 #include <algorithm>
 #include <queue>
 #include <deque>
 #include <queue>
 #include <list>
 #include <map>
 #include <set>
 #include <vector>
 #include <utility>
 #include <functional>
 #include <fstream>
 #include <iomanip>
 #include <sstream>
 #include <numeric>
 #include <cassert>
 #include <ctime>
 #include <iterator>
 const int INF = 0x3f3f3f3f;
 const int dir[][] = {{-,},{,},{,-},{,},{-,-},{-,},{,-},{,}};
 using namespace std;
 int main(void)
 {
     ios::sync_with_stdio(false);
     int n, V;
     int c[], f[];
     #ifndef ONLINE_JUDGE
     freopen("in.txt", "r", stdin);
     #endif // ONLINE_JUDGE
     while (cin>>n)
     {
         if(!n) break;
         for (int i = ; i < n; ++i) cin>>c[i];
         cin>>V;
         V-=;
         if (V<)
         {
             cout<<V+<<endl; continue;
         }
         int tmp=-, Max;
         for (int i = ; i <n; ++i)
             if(tmp<c[i]) tmp=c[i], Max=i;
         memset(f,,sizeof(f));
         for (int i=;i<n;++i)
         {
             if (i==Max) continue;
             for (int v = V; v>=c[i]; --v)
             {
                 f[v] = max(f[v], f[v-c[i]]+c[i]);
             }
         }
         cout<<V+-f[V]-c[Max]<<endl;
     }
     return ;
 }

囧