zoj1409 Communication System

 1 #include <iostream>
 2 #include <string.h>
 3 #include <stdio.h>
 4 #define inf 99999999
 5 using namespace std;
 6 int dp[105][10005];//i件设备，最小带宽（瓶颈）为j时的最小花费
 7 int B[105][105];
 8 int P[105][105];
 9 int M[105],N;
10 double fmax(double a,double b){
11     if(a>b) return a;else return b;
12 }
13 int main()
14 {
15 //    freopen("out.txt","w",stdout);
16     int t;
17     scanf("%d",&t);
18     while(t--){
19         scanf("%d",&N);
20         int MaxB=-1;
21         for(int i=1;i<=N;i++){
22             scanf("%d",&M[i]);
23             for(int j=1;j<=M[i];j++){
24                 scanf("%d%d",&B[i][j],&P[i][j]);
25                 MaxB=max(MaxB,B[i][j]);
26             }
27         }
28         for(int i=1;i<=N;i++){
29             for(int j=0;j<=MaxB;j++) dp[i][j]=inf;
30         }
31         for(int i=0;i<=MaxB;i++) dp[0][i]=0;
32 
33         for(int i=1;i<=N;i++){
34             for(int j=1;j<=M[i];j++){
35                 int b=B[i][j],p=P[i][j];
36                 //dp[i+1][b]=max(dp[i+1][b],dp[i][b’]+p) 当前的b最小...其中b‘>=b
37                 for(int bx=b;bx<=MaxB;bx++){
38                     dp[i][b]=max(dp[i][b],dp[i-1][bx]+p);
39                 }
40                 //dp[i+1][b‘]=max(dp[i+1][b‘],dp[i][b’]+p) 当前的b不是最小 ，其中b‘<=b
41                 for(int bx=0;bx<=b;bx++){
42                     dp[i][bx]=min(dp[i][bx],dp[i-1][bx]+p);
43                 }
44             }
45         }
46         double ans=-1;
47         for(int b=0;b<=MaxB;b++){
48             ans=fmax(ans,(b+0.0)/dp[N][b]);
49         }
50 
51         printf("%.3lf\n",ans);
52     }
53 
54     return 0;
55 }