#include <bits/stdc++.h>
#include "cyberland.h"
#define ll long long
#define pb push_back
#define fi first
#define se second
using namespace std;
const int N = 1e5+5;
const int K = 70+2;
vector<pair<int,int> > g[N];
double dist[N][K];
bool vis[N][K], vis2[N];
vector<int> starts, arr2;
void dfs(int u, int h)
{
vis2[u]=1;
if(arr2[u]==0)
starts.pb(u);
for(auto v:g[u])
if(!vis2[v.fi]&&v.fi!=h)
dfs(v.fi,h);
}
double solve(int n, int m, int k, int h, vector<int> x,
vector<int> y, vector<int> c, vector<int> arr)
{
k=min(k,70);
arr2=arr;
for(int i = 0;i<m;i++)
g[x[i]].pb({y[i],c[i]}),
g[y[i]].pb({x[i],c[i]});
for(int i = 0;i<n;i++)
for(int j = 0;j<=k;j++)
dist[i][j]=1e15,
vis[i][j]=0;
priority_queue<pair<double,pair<int,int> >,vector<pair<double,pair<int,int> > >,greater<pair<double,pair<int,int> > > > q[k+1];
dist[0][0]=0;
q[0].push({0,{0,0}});
for(int i = 0;i<n;i++)
vis2[i]=0;
dfs(0,h);
for(auto x:starts)
q[0].push({0,{x,0}}),
dist[x][0]=0;
starts.clear();
for(int i = 0;i<=k;i++)
vis[h][i]=1;
for(int qi = 0;qi<=k;qi++)
{
while(!q[qi].empty())
{
int u = q[qi].top().se.fi, dv = q[qi].top().se.se;
q[qi].pop();
if(vis[u][dv])
continue;
vis[u][dv]=1;
for(auto v:g[u])
{
double nwc = dist[u][dv]+v.se;
if(dist[v.fi][dv]>nwc)
dist[v.fi][dv]=nwc,
q[qi].push({nwc,{v.fi,dv}});
if(arr[v.fi]==2&&dv<k)
{
nwc/=2;
if(dist[v.fi][dv+1]>nwc)
dist[v.fi][dv+1]=nwc,
q[qi+1].push({nwc,{v.fi,dv+1}});
}
}
}
}
double best = 1e15;
for(int i = 0;i<=k;i++)
best=min(best,dist[h][i]);
for(int i = 0;i<n;i++)
g[i].clear();
if(best>=2e14)
return -1;
return best;
}
