[HDU 2955]Robberies (动态规划)

 1 #include <cstdio>
 2 #include <algorithm>
 3 #include <cstring>
 4 #include <cmath>
 5 using namespace std;
 6 
 7 const int MAX_N = 110;
 8 const double EPS = 1e-8;
 9 double dp[MAX_N][MAX_N*MAX_N];
10 int T,N,m[MAX_N];
11 double P,p[MAX_N];
12 
13 int main(){
14     scanf("%d",&T);
15     while( T-- ){
16         scanf("%lf%d",&P,&N);
17         P = 1 - P;
18         int summ = 0;
19         for(int i=1;i<=N;i++){
20             scanf("%d%lf",&m[i],&p[i]);
21             p[i] = 1 - p[i];
22             summ += m[i];
23         }
24         //for(int i=0;i<=summ;i++) dp[1][i] = 1;
25         dp[0][0] = 1;
26         for(int i=1;i<=N;i++){
27             for(int j=0;j<=summ;j++){
28                 if( j-m[i]>=0 ) dp[i][j] = max(dp[i-1][j],dp[i-1][j-m[i]]*p[i]);
29                 else dp[i][j] = dp[i-1][j];
30             }
31         }
32         int ans = 0;
33         for(int i=0;i<=summ;i++){
34 //            printf("%f\n",dp[N][i]);
35             if( P-dp[N][i]<=EPS ){
36 //                printf("dp[N][i]=%f < P=%f\n",dp[N][i],P);
37                 ans = i;
38             }
39         }
40 //        puts("");
41         printf("%d\n",ans);
42     }
43     return 0;
44 }
45 
46 /*
47 3
48 0.04 3
49 1 0.02
50 2 0.03
51 3 0.05
52 0.06 3
53 2 0.03
54 2 0.03
55 3 0.05
56 0.10 3
57 1 0.03
58 2 0.02
59 3 0.05
60 */