floyd Arbitrage（floyd） 1A水过

#include<stdio.h>
#include<cstring>
char a[35][100],b[100],c[100];
int n;
double grid[35][35];
int exc(char str[100])
{
    for (int i=0;i<n;i++)
        if(strcmp(a[i],str)==0)
        return i;
    return 0;
}
int floyd()
{
    int i,j,k;
    double m;
    for (i=0;i<n;i++)
        for (j=0;j<n;j++)
             for (k=0;k<n;k++)
            {
                m=grid[i][k]*grid[k][j];
                if (m>grid[i][j])
                    grid[i][j]=m;
            }
    for (i=0;i<n;i++)
        if(grid[i][i]>1)
        return 1;
    return 0;
}
int main()
{
    int i=1,j,m;
    double rate;
    while(scanf("%d",&n)!=EOF)
    {
        if (n==0)   break;
        memset (grid,0,sizeof(grid));
        for (j=0;j<n;j++)
            scanf("%s",a[j]);
        scanf("%d",&m);
        while (m--)
        {
            scanf("%s%lf%s",b,&rate,c);
            grid[exc(b)][exc(c)]=rate;
        }
        printf("Case %d: ",i++);
        if (floyd())
            printf("Yes\n");
        else
            printf("No\n");
    }
    return 0;
}