rt，本地(Dev-C++5.11)跑样例，输出为0，但交上去，直接AC？！

#include<iostream>
#include<cstring>
#include<queue>
#define re register
#define double long double
using namespace std;

const int N = 1e6;

int cnt,n,m,a,b;
int head[N];
double dis[N];
bool vis[N];

struct edge{
	int v,next;
	double w;
}e[N];

inline void add(int u,int v,double w){
	cnt ++;
	e[cnt].v = v;
	e[cnt].w = 1.00000000 - (double)(w / 100);
	e[cnt].next = head[u];
	head[u] = cnt;
}

inline void dijkstra(){
	typedef pair<double,int> p;
	priority_queue<p,vector<p>,less<p> > q;
	vis[a] = true;
	dis[a] = 1;
	q.push(make_pair(dis[a],a));
	while(! q.empty()){
		int u = q.top().second;
		q.pop();
		vis[u] = false;
		for(re int i = head[u];i != -1;i = e[i].next){
			int v = e[i].v;
			if(dis[v] < dis[u] * e[i].w){
				dis[v] = dis[u] * e[i].w;
				if(! vis[v]){
					vis[v] = true;
					q.push(make_pair(dis[v],v));
				}
			}
		}
	}
}

inline void cs(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	memset(head,-1,sizeof(head));
	memset(dis,-0x3f,sizeof(dis));
}

int main(){
	cs();
	cin>>n>>m;
	for(re int i = 1;i <= m;i ++){
		int x,y;
		double z;
		cin>>x>>y>>z;
		add(x,y,z);
		add(y,x,z);
	}
	cin>>a>>b;
	dijkstra();
	printf("%.8llf\n",100.00000000 / dis[b]);
	return 0;
}