#include "cyberland.h"
#include <bits/stdc++.h>
using namespace std;
typedef double ld;
const long long INF = 1e18;
const int MAXK = 67;
vector<pair<int,int>> con[100005];
vector<int> tip;
ld dist[MAXK+1][100005];
bool visited[100005];
void dfs(int nod, int H)
{
visited[nod]=1;
for(auto [adj,c]:con[nod])
if(!visited[adj] && adj!=H)
dfs(adj,H);
}
double solve(int N, int M, int K, int H, std::vector<int> x, std::vector<int> y, std::vector<int> c, std::vector<int> arr) {
K = min(K, MAXK);
for(int i=0;i<N;i++)
{
con[i].clear();
visited[i]=0;
}
tip = arr;
for(int i=0;i<M;i++)
{
con[x[i]].push_back({y[i],c[i]});
con[y[i]].push_back({x[i],c[i]});
}
dfs(0,H);
for(int nr=0;nr<=K;nr++)
for(int i=0;i<N;i++)
dist[nr][i]=INF;
priority_queue<pair<ld,pair<int,int>>> pq;
for(int i=0;i<N;i++)
{
if(i==0 || (visited[i] && tip[i]==0))
{
pq.push({0,{0,i}});
dist[0][i]=0;
}
}
while(!pq.empty())
{
ld cdist = -pq.top().first;
int nod = pq.top().second.second;
int cnt = pq.top().second.first;
pq.pop();
if(cdist!=dist[cnt][nod])
continue;
for(auto [adj,c]:con[nod])
{
if(adj==H)
{
if(tip[adj]==0)
dist[0][adj]=0;
else if(tip[adj]==2)
dist[0][adj]=min(dist[0][adj], (cdist+(ld)c)/2);
else
dist[0][adj]=min(dist[0][adj], cdist+c);
}
else if(tip[adj]==2)
{
if(dist[cnt][adj] > cdist + c)
{
dist[cnt][adj] = cdist + c;
pq.push({-dist[cnt][adj],{cnt,adj}});
}
if(cnt+1<=K && dist[cnt+1][adj] > (cdist + (ld)c)/2)
{
dist[cnt+1][adj] = (cdist + (ld)c)/2;
pq.push({-dist[cnt+1][adj],{cnt+1,adj}});
}
}
else if(tip[adj]==1)
{
if(dist[cnt][adj] > cdist + c)
{
dist[cnt][adj] = cdist + c;
pq.push({-dist[cnt][adj],{cnt,adj}});
}
}
}
}
ld mnm=INF;
for(int cnt=0;cnt<=K;cnt++)
mnm = min(mnm, dist[cnt][H]);
if(mnm==INF)
return -1;
else
return mnm;
}
