poj 2240 Arbitrage

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <cstdlib>
 4 #include <algorithm>
 5 #include <iostream>
 6 using namespace std;
 7 #define maxn 35
 8 char name[maxn][maxn];//各种货币的名字
 9 double map[maxn][maxn];//map[i][j]i-->j的汇率
10 int n;
11 
12 void init ();
13 int find (char str[]);
14 void floyd ();
15 
16 int main ()
17 {
18     int m, i, j, k = 0;
19     double s;
20     char str1[maxn], str2[maxn];
21 
22     while (scanf ("%d", &n), n)
23     {
24         init();
25         for (i=0; i<n; i++)
26             scanf ("%s", name[i]);
27         scanf ("%d", &m);
28         while (m --)
29         {
30             scanf ("%s %lf %s", str1, &s, str2);
31             int a = find (str1);
32             int b = find (str2);
33             map[a][b] = s;
34         }
35         floyd();
36         m = 0;
37         for (i=0; i<n; i++)
38                 if (map[i][i] > 1)
39                     m = 1;
40         if ( m )
41             printf ("Case %d: Yes\n", ++k);
42         else
43             printf ("Case %d: No\n", ++k);
44     }
45     return 0;
46 }
47 
48 void init ()//初始化为一
49 {
50     int i, j;
51     for (i=0; i<n; i++)
52         for (j=0; j<n; j++)
53             map[i][j] = 1;
54 }
55 int find (char str[])
56 {
57     int i;
58     for (i=0; i<n; i++)
59         if (!strcmp(name[i], str))
60             return i;
61 }
62 void floyd ()
63 {
64     int i, j, k;
65     for (i=0; i<n; i++)
66         for (k=0; k<n; k++)
67             for (j=0; j<n; j++)
68                 map[i][j] = max (map[i][j], map[i][k]*map[k][j]);
69 }