poj1787 Charlie's Change

思路：

完全背包，记录路径。

实现：

 #include <bits/stdc++.h>
 using namespace std;
 const int INF = 0x3f3f3f3f;
 int v[] = {, , , };
 int c[], m;
 int dp[], used[], path[];
 int main()
 {
     while (cin >> m >> c[] >> c[] >> c[] >> c[], m || c[] || c[] || c[] || c[])
     {
         memset(used, , sizeof used);
         memset(path, , sizeof path);
         path[] = -;
         for (int i = ; i <= m; i++) dp[i] = -INF;
         dp[] = ;
         for (int i = ; i < ; i++)
         {
             memset(used, , sizeof used);
             for (int j = v[i]; j <= m; j++)
             {
                 if (dp[j - v[i]] != -INF && dp[j - v[i]] +  > dp[j] && used[j - v[i]] < c[i])
                 {
                     dp[j] = dp[j - v[i]] + ;
                     used[j] = used[j - v[i]] + ;
                     path[j] = j - v[i];
                 }
             }
         }
         if (dp[m] <= -INF) { cout << "Charlie cannot buy coffee." << endl; }
         else
         {
             int ans[]; memset(ans, , sizeof ans);
             while (path[m] != -)
             {
                 ans[m - path[m]]++;
                 m = path[m];
             }
             cout << "Throw in " << ans[v[]] << " cents, " << ans[v[]] << " nickels, " << ans[v[]] << " dimes, and " << ans[v[]] << " quarters." << endl;
         }
     }
     return ;
 }