#include <bits/stdc++.h>
#include "cyberland.h"
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
#define MASK(i) (1LL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
#define ALL(v) (v).begin(), (v).end()
ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
ll LASTBIT(ll mask){return (mask) & (-mask);}
int pop_cnt(ll mask){return __builtin_popcountll(mask);}
int ctz(ll mask){return __builtin_ctzll(mask);}
int logOf(ll mask){return __lg(mask);}
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rngesus(ll l, ll r){return l + (ull) rng() % (r - l + 1);}
template <class T1, class T2>
bool maximize(T1 &a, T2 b){
if (a < b) {a = b; return true;}
return false;
}
template <class T1, class T2>
bool minimize(T1 &a, T2 b){
if (a > b) {a = b; return true;}
return false;
}
template <class T>
void printArr(T& container, char separator = ' ', char finish = '\n'){
for(auto item: container) cout << item << separator;
cout << finish;
}
template <class T>
void remove_dup(vector<T> &a){
sort(ALL(a));
a.resize(unique(ALL(a)) - a.begin());
}
struct P{
int i; ll w;
P(){}
P(int _i, ll _w){i = _i, w = _w;}
};
struct compare{
bool operator () (P a, P b){return a.w > b.w;}
};
const int N = 1e5 + 69;
const int K = 69;
const ll INF = 2e18 + 69;
int h;
bool visited[N];
double dis[N];
vector<P> graph[N];
void dfs(int u){
visited[u] = true;
if (u == h) return;
for(auto v: graph[u]) if (!visited[v.i]) dfs(v.i);
}
double solve(int n, int m, int k, int _h, vector<int> x, vector<int> y, vector<int> c, vector<int> arr) {
h = _h;
minimize(k, K);
for(int i= 0; i<n; ++i){
graph[i].clear();
visited[i] = false;
dis[i] = INF;
}
for(int i = 0; i<m; ++i){
int u = x[i], v = y[i], w = c[i];
graph[u].push_back(P(v, w));
graph[v].push_back(P(u, w));
}
dfs(0);
if (!visited[h]) return -1;
priority_queue<P, vector<P>, compare> pq;
for(int i = 0; i<n; ++i) if (visited[i] && (arr[i] == 0 || i == 0)){
dis[i] = 0;
pq.push(P(i, 0));
}
double ans = INF;
for(int iteration = 0; iteration <= k; ++iteration){
if (pq.empty()) exit(1);
while(pq.size()){
P u = pq.top(); pq.pop();
if (u.i == h) continue;
if (dis[u.i] < u.w) break;
for(P v: graph[u.i]) if (minimize(dis[v.i], dis[u.i] + v.w))
pq.push(P(v.i, dis[v.i]));
}
minimize(ans, dis[h]);
for(int i = 0; i<n; ++i) if (visited[i]){
if (arr[i] != 2) dis[i] = INF;
else{
dis[i] /= 2;
pq.push(P(i, dis[i]));
}
}
}
return ans;
}
// int main(void){
// ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
// cout << solve(4, 4, 30, 3, {0, 0, 1, 2}, {1, 2, 3, 3}, {5, 4, 2, 4}, {1, 0, 2, 1}) << "\n";
// return 0;
// }
