POJ2240

floyd

题意：给定一些money以及之间的转化，询问最后能不能让某种money升值

 

View Code

 1 #include<stdio.h>

 2 #include<map>

 3 #include<string>

 4 #include<iostream>

 5 using namespace std;

 6 const int maxn = 105;

 7 map<string,int>mp;

 8 double mat[ maxn ][ maxn ];

 9 double fmax( double a ,double b ){

10     return a>b?a:b;

11 }

12 int main(){

13     int n;

14     int cnt=1;

15     while( scanf("%d",&n)==1,n ){

16         string s;

17         for( int i=1;i<=n;i++ ){

18             cin>>s;

19             mp[ s ]=i;

20         }

21         int m;

22         scanf("%d",&m);

23         string s1,s2;

24         double tmp;

25         for( int i=0;i<maxn;i++ )

26             for( int j=0;j<maxn;j++ )

27                 if( i==j )

28                     mat[ i ][ j ]=1.0;

29                 else

30                     mat[ i ][ j ]=0.0;

31         for( int i=1;i<=m;i++ ){

32             cin>>s1;

33             cin>>tmp;

34             cin>>s2;

35             mat[ mp[ s1 ] ][ mp[ s2 ] ]=tmp;

36         }

37         for( int k=1;k<=n;k++ ){

38             for( int i=1;i<=n;i++ ){

39                 for( int j=1;j<=n;j++ ){

40                     if( mat[i][k]>0 && mat[k][j]>0 ){

41                         mat[i][j]=fmax( mat[i][j],mat[i][k]*mat[k][j]);

42                     }

43                 }

44             }

45         }

46         int flag=-1;

47         for( int i=1;i<=n;i++ )

48             if( mat[i][i]>1 ){

49                 flag=1;

50                 break;

51             }

52         printf("Case %d: ",cnt++);

53         if( flag==1 )printf("Yes\n");

54         else printf("No\n");

55     }

56     return 0;

57 }