hdu-1217 Arbitrage

http://acm.hdu.edu.cn/showproblem.php?pid=1217

注意这里不能用Dijkstra，因为乘法中小于1相当于加法中的小于0

#include "stdio.h"#include "iostream"#include "string"#include "map"using namespace std;const int maxn = 205;map<string,int>curr;string a,b;int n;double maps[maxn][maxn];void Floyd(){    for( int k=1;k<=n;k++ ){for( int i=1;i<=n;i++ ){for( int j=1;j<=n;j++ ){if( maps[i][j] < maps[i][k] * maps[k][j] )maps[i][j] = maps[i][k] * maps[k][j];}}}}int main(){    int i,j,m,cas=1;    double rate;    while( scanf("%d",&n)!=EOF ,n)    {        for( i=1;i<=n;i++ )        {            for( j=1;j<=n;j++ )            {                maps[i][j] = 0.0;            }        }        for( i=1; i<=n; i++ )        {            cin>>a;            curr[a]=i;        }        scanf("%d",&m);        for( i=1;i<=m;i++ )        {            cin>>a>>rate>>b;            maps[curr[a]][curr[b]] = rate;        }        Floyd();        if( maps[1][1]>1.0 )            printf("Case %d: Yes\n",cas++);        else            printf("Case %d: No\n",cas++);    }    return 0;}