pku1018 Communication System

http://poj.org/problem?id=1018

DP，写的好蒙。。。

 1 #include <stdio.h>
 2 #include <map>
 3 
 4 using namespace std;
 5 
 6 #define N 110
 7 
 8 int b[N][N], p[N][N];
 9 int dp[N][N*N];
10 const int maxint = 1<<30;
11 
12 int main()
13 {
14     int i, j, t, n, m, x, y, k;
15     float max1, temp1;
16     map<int, int> map1, map2;
17     map<int, int>::iterator it;
18     scanf("%d", &t);
19     while(t-- && scanf("%d", &n))
20     {
21         map1.clear();
22         map2.clear();
23         k = 1;
24         for(i=1; i<=n; i++)
25         {
26             scanf("%d", &m);
27             b[i][0] = m;
28             for(j=1; j<=m; j++)
29             {
30                 scanf("%d%d", &x, &y);
31                 if(map1.find(x) == map1.end())
32                 {
33                     map1.insert(make_pair(x, k));
34                     k ++;
35                 }
36                 b[i][j] = x;
37                 p[i][j] = y;
38             }
39         }
40         for(i=0; i<N*N; i++)
41         {
42             dp[0][i] = dp[1][i] = maxint;
43         }
44         for(j=1; j<=b[1][0]; j++)
45         {
46             dp[0] [map1[b[1][j]]] = min(dp[0] [map1[b[1][j]]], p[1][j]);
47         }
48         for(i=2; i<=n; i++)
49         {
50             for(j=1; j<=b[i][0]; j++)
51             {
52                 for(it=map1.begin(); it!=map1.end(); it++)
53                 {
54                     if(dp[0][(*it).second]==maxint)
55                     {
56                         continue;
57                     }
58                     if((*it).first <= b[i][j])
59                     {
60                         dp[1][map1[(*it).first]] = min(dp[1][map1[(*it).first]], dp[0][map1[(*it).first]]+p[i][j]);
61                     }
62                     else
63                     {
64                         dp[1][map1[b[i][j]]] = min(dp[1][map1[b[i][j]]], dp[0][map1[(*it).first]]+p[i][j]);
65                     }
66                 }
67             }
68             for(j=0; j<N*N; j++)
69             {
70                 dp[0][j] = dp[1][j];
71                 dp[1][j] = maxint;
72             }
73         }
74         for(it=map1.begin(); it!=map1.end(); it++)
75         {
76             map2.insert(make_pair((*it).second, (*it).first));
77         }
78         max1 = -1;
79         for(j=0; j<N*N; j++)
80         {
81             if(dp[0][j]==maxint)
82             {
83                 continue;
84             }
85             temp1 = (float)map2[j] / (float)dp[0][j];
86             if(temp1 > max1)
87             {
88                 max1 = temp1;
89             }
90         }
91         printf("%.3f\n", max1);
92     }
93     return 0;
94 }

 

posted @ 2013-01-20 23:51  Yuan1991  阅读(130)  评论(0)  编辑  收藏  举报