最短路—1008

计算汇率，用Floyd，最后检查对角线上的树是不是大于1

#include<stdio.h>
#include<string.h>
struct node
{
    char name[30];
} c[33];
double map[33][33];
int main()
{
    int n,m,i,j,k,cc=0;
    while(scanf("%d",&n)&&n!=0)
    {
        cc++;
        for(i=0; i<n; i++)
        {
            scanf("%s",c[i].name);
            map[i][i]=1;
            for(j=i+1; j<n; j++)
                map[i][j]=map[j][i]=0;
        }
        scanf("%d",&m);
        for(i=0; i<m; i++)
        {
            char x[30],y[30];
            int xx,yy;
            double s;
            scanf("%s%lf%s",x,&s,y);
            for(j=0; j<n; j++)
            {
                if(strcmp(x,c[j].name)==0)
                    xx=j;
                if(strcmp(y,c[j].name)==0)
                    yy=j;
            }
            if(map[xx][yy]<s)
                map[xx][yy]=s;
        }
        for(k=0; k<n; k++)
            for(i=0; i<n; i++)
                for(j=0; j<n; j++)
                    if(map[i][j]<map[i][k]*map[k][j])
                        map[i][j]=map[i][k]*map[k][j];
        int f=0;
        for(i=0; i<n; i++)
            if(map[i][i]>1)
            {
                f=1;
                break;
            }
        if(f==1)
            printf("Case %d: Yes\n",cc);
        else
            printf("Case %d: No\n",cc);
    }
    return 0;
}
/*
3
USDollar
BritishPound
FrenchFranc
3
USDollar 0.5 BritishPound
BritishPound 10.0 FrenchFranc
FrenchFranc 0.21 USDollar
3
USDollar
BritishPound
FrenchFranc
6
USDollar 0.5 BritishPound
USDollar 4.9 FrenchFranc
BritishPound 10.0 FrenchFranc
BritishPound 1.99 USDollar
FrenchFranc 0.09 BritishPound
FrenchFranc 0.19 USDollar
*/