Hdu--Arbitrage(Floyd)

Original title link
floyd deformation, there's really nothing
to lose, it costs too much food or gas waited a long time. .
Code

#include<stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;
double map[50][50];
int n,inf=9999999,flag;
void floyd()
{
    int i,j,k;
    for(k=1;k<=n;k++)
    {
        for(i=1;i<=n;i++)
        {
            for(j=1;j<=n;j++)
            {
                if(map[i][j]<map[i][k]*map[k][j])
                    map[i][j]=map[i][k]*map[k][j];
            }
        }
    }
    for(i=1;i<=n;i++)
    {
        if(map[i][i]>1)
        {
            flag=1;
            break;
        }
    }
}
int main()
{
    int i,j,q=1,m;
    double cos;
    char s[30][30],s1[30],s2[30];
    while(~scanf("%d",&n)&&n)
    {
        getchar();
        memset(map,0,sizeof(map));
        for(i=1;i<=n;i++)
            scanf("%s",s[i]);
       /* for(i=1;i<=n;i++)
            printf("%s\n",s[i]);*/
        scanf("%d",&m);
        while(m--)
        {
            getchar();
            scanf("%s %lf %s",s1,&cos,s2);
            for(i=1;i<=n;i++)
            {
                if(strcmp(s[i],s1)==0)
                    break;
            }
            for(j=1;j<=n;j++)
            {
                if(strcmp(s[j],s2)==0)
                    break;
            }
            map[i][j]=cos;//printf("%d %lf %d\n",i,cos,j);
        }
      /*  for(i=1;i<=n;i++)
       {
           for(j=1;j<=n;j++)
        {
            printf("%f ",map[i][j]);
        }printf("\n");
       }*/
        flag=0;
        floyd();
        printf("Case %d: ",q++);
        if(flag)  printf("Yes\n");
        else  printf("No\n");
    }
    return 0;
}