[POJ 1787]Charlie's Change (动态规划)

 1 #include <cstdio>
 2 #include <algorithm>
 3 #include <cstring>
 4 #include <cmath>
 5 #include <map>
 6 #include <iterator>
 7 #include <vector>
 8 using namespace std;
 9 typedef long long LL;
10 
11 const int INF = 99999999;
12 
13 int P,c[10],v[10];
14 int dp[11000];
15 int fa[11000][10];
16 
17 int main(){
18     v[1] = 1;
19     v[2] = 5;
20     v[3] = 10;
21     v[4] = 25;
22     while(1){
23         scanf("%d",&P);
24         for(int i=1;i<=4;i++) scanf("%d",&c[i]);
25         if( P==0 && c[1]==0&&c[2]==0&&c[3]==0&&c[4]==0){
26             break;
27         }
28         for(int j=0;j<11000;j++){
29             dp[j] = -INF;
30         }
31         dp[0] = 0;
32         memset(fa,0,sizeof(fa));
33         for(int i=1;i<=4;i++){
34             if( c[i]*v[i]>P ){
35                 for(int j=v[i];j<=P;j++) {
36                     if( dp[j]<dp[j-v[i]]+1){
37                         dp[j] = dp[j-v[i]]+1;
38                         if( dp[j]<=0 ) continue;
39                         for(int k=1;k<=4;k++){
40                             if( k==i ) fa[j][k] = fa[j-v[i]][k] + 1;
41                             else fa[j][k] = fa[j-v[i]][k];
42                         }
43                     }
44 //                    dp[j] = max(dp[j],dp[j-v[i]]+1);
45                 }
46             } else {
47                 int k = 1;
48                 while( k<c[i] ){
49                     for(int j=P;j>=v[i]*k;j--){
50                         if( dp[j]<dp[j-v[i]*k]+k ){
51                             dp[j] = dp[j-v[i]*k]+k ;
52 //                            if( dp[j]>=0 ) fa[j][i] = fa[j-v[i]*k][i] + k;
53                             if( dp[j] <=0 ) continue;
54                             for(int e=1;e<=4;e++){
55                                 if( e==i ) fa[j][e] = fa[j-v[i]*k][e] + k;
56                                 else fa[j][e] = fa[j-v[i]*k][e];
57                             }
58                         }
59 //                        dp[j] = max(dp[j],dp[j-v[i]*k]+k);
60                     }
61                     c[i] -= k;
62                     k <<= 1;
63                 }
64                 if( c[i]<=0 ) continue;
65                 for(int j=P;j>=v[i]*c[i];j--){
66                     if( dp[j]<dp[j-v[i]*c[i]] + c[i] ){
67                         dp[j] = dp[j-v[i]*c[i]] + c[i];
68                         if( dp[j] <=0 ) continue;
69                         for(int e=1;e<=4;e++){
70                             if( e==i ) fa[j][e] = fa[j-v[i]*c[i]][e] + c[i];
71                             else fa[j][e] = fa[j-v[i]*c[i]][e];
72                         }
73                     }
74 //                    dp[j] = max(dp[j],dp[j-v[i]*c[i]] + c[i]  );
75                 }
76             }
77         }
78         if( dp[P] <=0 ) puts("Charlie cannot buy coffee.");
79         else printf("Throw in %d cents, %d nickels, %d dimes, and %d quarters.\n",fa[P][1],fa[P][2],fa[P][3],fa[P][4]);
80     }
81     return 0;
82 }