emmmmm又是SPFA没啥好讲的板子题
#include <iostream>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <string>
#include <map>
#include <iomanip>
#include <algorithm>
#include <queue>
#include <stack>
#include <set>
#include <vector>
//const int maxn = 1e5+5;
#define ll long long
ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
ll lcm(ll a,ll b){return a/gcd(a,b)*b;}
//const int inf = 0x6fffffff;
#define MAX INT_MAX
#define FOR(i,a,b) for( int i = a;i <= b;++i)
#define bug cout<<"--------------"<<endl
using namespace std;
string s[35];
int ver[1100],next[1100],head[1100],ans[1100],vis[1100];
double edge[1100],d[1100];
int tot,n;
void add(int x,int y,double z)
{
ver[++tot] = y,edge[tot] = z,next[tot] = head[x] , head[x] = tot;
}
int spfa(int first)
{
memset(vis,0,sizeof(vis));
memset(d,0,sizeof(d));
memset(ans,0,sizeof(ans));
d[first] = 10;
vis[first] = 1;
ans[first] ++;
queue<int>que;
que.push(first);
while(que.size())
{
int x = que.front();que.pop();
vis[x] = 0;
// cout<<x<<" ";
// FOR(i,1,3)
// cout<<vis[i]<<" ";
// cout<<endl;
for(int i=head[x];i;i=next[i])
{
int y = ver[i];
double z = edge[i];
// cout<<y<<" "<<d[y]<<" "<<d[x]*z<<endl;
if(d[y] <(double) d[x] * z)
{
d[y] =(double) d[x] * z;
if(vis[y] == 1) continue;
vis[y] = 1;
que.push(y);
ans[y]++;
if(ans[y] >= n)
{
return 1;
}
}
}
}
return 0;
}
void clearr()
{
tot = 0;
memset(head,0,sizeof(head));
memset(next,0,sizeof(next));
memset(ver,0,sizeof(ver));
memset(edge,0,sizeof(edge));
}
int main()
{
// freopen("C:\Users\方瑞\Desktop\input.txt","r",stdin);
// freopen("C:\Users\方瑞\Desktop\output.txt","w",stdout);
ios::sync_with_stdio(false);
int casee=0;
while((cin>>n) && n)
{
clearr();
FOR(i,1,n) cin>>s[i];
int m;
cin>>m;
while(m--)
{
string s1,s2;
double hhh;
cin>>s1>>hhh>>s2;
int fx,fy;
for(int i=1;i<=n;++i)
{
if(s[i] == s1) fx = i;
if(s[i] == s2) fy = i;
}
// cout<<fx<<" "<<fy<<" "<<hhh<<endl;
add(fx,fy,hhh);
}
int flag = 0;
for(int i=1;i<=n;++i)
{
if(spfa(i) == 1)
{
flag = 1;
break;
}
}
if(flag == 1) cout<<"Case "<<++casee<<": Yes"<<endl;
else cout<<"Case "<<++casee<<": No"<<endl;
}
}