#include "cyberland.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long lo;
#define fi first
#define se second
#define int long long
#define pb push_back
const lo inf = 1000000000000000000;
const lo li = 100005;
int n,m,k;
int arr[li],flag,t,vis[li][100],h,connected[li];
double pw[100];
vector<pair<int,int>> v[li];
vector<int> vec;
inline void dfss(int node){
if(connected[node])return;
connected[node]=1;
if(node==h)return ;
for(auto go:v[node]){
if(connected[go.fi]==0)dfss(go.fi);
}
}
inline double sp(){
priority_queue<pair<double,pair<int,int>>> pq;
for(auto go:vec){
for(int i=0;i<=k;i++){
pq.push({0,{i,go}});
}
}
flag=0;
while(pq.size()){
double tim=-pq.top().fi;
int div=pq.top().se.fi;
int node=pq.top().se.se;
pq.pop();
if(div<0)continue;
if(vis[node][div])continue;
vis[node][div]=1;
if(node==h && div==0)
return tim;
if(node==h)continue;
for(auto go:v[node]){
int yes=div;
if (vis[go.fi][yes]==0)
pq.push({-tim-go.se/pw[div],{yes,go.fi}});
if(arr[go.fi]==2){
yes--;
if(yes>=0 && vis[go.fi][yes]==0)
pq.push({-tim-go.se/pw[div],{yes,go.fi}});
}
}
}
return -1;
}
double solve(int32_t N, int32_t M, int32_t K, int32_t H,
vector<int32_t> x,vector<int32_t> y,vector<int32_t> c,vector<int32_t> _arr){
pw[0]=1;
for(int i=1;i<=95;i++){
pw[i]=pw[i-1]+pw[i-1];
}
n=N;
m=M;
k=min(K,95);
h=H;
vec.clear();
vec.pb(0);
for(int i=0;i<n;i++){
v[i].clear();
connected[i]=0;
for(int j=0;j<=k;j++)vis[i][j]=0;
arr[i]=_arr[i];
}
for(int i=0;i<m;i++){
v[x[i]].pb({y[i],c[i]});
v[y[i]].pb({x[i],c[i]});
}
dfss(0);
for(int i=0;i<n;i++){
if(arr[i]==0 && connected[i])vec.pb(i);
}
if(connected[h]==0) return -1;
return sp();
}
