#include <bits/stdc++.h>
#include "cyberland.h"
#pragma GCC optimize("Ofast")
#pragma comment(linker, "/stack:200000000")
#pragma GCC target( "sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native" )
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("profile-values,profile-reorder-functions,tracer")
#pragma GCC optimize("vpt")
#pragma GCC optimize("rename-registers")
#pragma GCC optimize("move-loop-invariants")
#pragma GCC optimize("unswitch-loops")
#pragma GCC optimize("function-sections")
#pragma GCC optimize("data-sections")
#pragma GCC optimize("branch-target-load-optimize")
#pragma GCC optimize("branch-target-load-optimize2")
#pragma GCC optimize("btr-bb-exclusive")
#pragma GCC optimize("inline")
#pragma GCC optimize("-fgcse")
#pragma GCC optimize("-fgcse-lm")
#pragma GCC optimize("-fipa-sra")
#pragma GCC optimize("-ftree-pre")
#pragma GCC optimize("-ftree-vrp")
#pragma GCC optimize("-fpeephole2")
#pragma GCC optimize("-ffast-math")
#pragma GCC optimize("-fsched-spec")
#pragma GCC optimize("-falign-jumps")
#pragma GCC optimize("-falign-loops")
#pragma GCC optimize("-falign-labels")
#pragma GCC optimize("-fdevirtualize")
#pragma GCC optimize("-fcaller-saves")
#pragma GCC optimize("-fcrossjumping")
#pragma GCC optimize("-fthread-jumps")
#pragma GCC optimize("-freorder-blocks")
#pragma GCC optimize("-fschedule-insns")
#pragma GCC optimize("inline-functions")
#pragma GCC optimize("-ftree-tail-merge")
#pragma GCC optimize("-fschedule-insns2")
#pragma GCC optimize("-fstrict-aliasing")
#pragma GCC optimize("-falign-functions")
#pragma GCC optimize("-fcse-follow-jumps")
#pragma GCC optimize("-fsched-interblock")
#pragma GCC optimize("-fpartial-inlining")
#pragma GCC optimize("no-stack-protector")
#pragma GCC optimize("-freorder-functions")
#pragma GCC optimize("-findirect-inlining")
#pragma GCC optimize("-fhoist-adjacent-loads")
#pragma GCC optimize("-frerun-cse-after-loop")
#pragma GCC optimize("inline-small-functions")
#pragma GCC optimize("-finline-small-functions")
#pragma GCC optimize("-ftree-switch-conversion")
#pragma GCC optimize("-foptimize-sibling-calls")
#pragma GCC optimize("-fexpensive-optimizations")
#pragma GCC optimize("inline-functions-called-once")
#pragma GCC optimize("-fdelete-null-pointer-checks")
#pragma GCC tartget("avx2")
using namespace std;
#define F first
#define S second
#define pb push_back
#define pii pair<int,int>
const int MAX=1e5+15;
const double inf=1e18;
double solve(int n,int m,int k,int h,vector<int> x,vector<int> y,vector<int> c,vector<int> arr){
vector<pii> g[n+1];
double dp[n+1][67];
for(int i=0;i<m;i++){
x[i]++;
y[i]++;
g[x[i]].pb({y[i],c[i]});
g[y[i]].pb({x[i],c[i]});
// cout<<x[i]<<" "<<y[i]<<" "<<c[i]<<"\n";
}
k=min(k,66);
h++;
for(int i=1;i<=n;i++){
for(int j=0;j<=k;j++)dp[i][j]=inf;
}
dp[1][0]=0;
priority_queue<pair<double,pii>> q;
q.push({0,{1,0}});
while(!q.empty()){
int v=q.top().S.F,c=q.top().S.S;
if(dp[v][c]<-q.top().F||v==h){
q.pop();
continue;
}
q.pop();
// cout<<v<<" "<<c<<" "<<dp[v][c]<<"\n";
for(auto to:g[v]){
if(arr[to.F-1]==0){
if(dp[to.F][c]>0){
dp[to.F][c]=0;
q.push({-dp[to.F][c],{to.F,c}});
}
}
else if(arr[to.F-1]==1){
if(dp[v][c]+to.S<dp[to.F][c]){
dp[to.F][c]=dp[v][c]+to.S;
q.push({-dp[to.F][c],{to.F,c}});
}
}
else{
if(dp[v][c]+to.S<dp[to.F][c]){
dp[to.F][c]=dp[v][c]+to.S;
q.push({-dp[to.F][c],{to.F,c}});
}
if(c+1<=k&&(dp[v][c]+to.S)/2<dp[to.F][c+1]){
dp[to.F][c+1]=(dp[v][c]+to.S)/2;
q.push({-dp[to.F][c+1],{to.F,c+1}});
}
}
}
}
double ans=inf;
for(int i=0;i<=k;i++)ans=min(ans,dp[h][i]);
if(ans==inf)return -1.0;
return ans;
}
// int main(){
// ios_base::sync_with_stdio(0);
// cin.tie(0);
// cout.tie(0);
// int t;
// cin>>t;
// cout.precision(10);
// while(t--){
// int n,m,k,h;
// cin>>n>>m>>k>>h;
// vector<int> arr(n);
// for(int i=0;i<n;i++)cin>>arr[i];
// vector<int> x(m),y(m),c(m);
// for(int i=0;i<m;i++)cin>>x[i]>>y[i]>>c[i];
// cout<<fixed<<solve(n,m,k,h,x,y,c,arr)<<"\n";
// }
// }
