P1576 最小花费


#include
using namespace std;
int head[200010],tim;
double dis[200010];
bool flag[200010];
struct csz
{
	int to;
	double w;
	int next;
}edge[200010];
void add(int u,int v,double w)
{
	edge[++tim].to=v;
	edge[tim].w=1.0-w/100.0;
	edge[tim].next=head[u];
	head[u]=tim;
}
void Dijkstra(int s)
{
	priority_queue >q;
	q.push({0,s});
	while(!q.empty())
	{
		int pos=q.top().second;
		q.pop();
		if(flag[pos])
			continue;
		flag[pos]=1;
		for(int i=head[pos];i;i=edge[i].next)
		{
			int to=edge[i].to;
			if(dis[to]>n>>m;
	for(int i=1;i<=m;i++)
	{
		cin>>u>>v>>w;
		add(u,v,w);
		add(v,u,w);
	}
	int a,b;
	cin>>a>>b;
	dis[a]=1.0;
	Dijkstra(a);
	printf("%.8lf",100.0/dis[b]);
	return 0;
}