#include "cyberland.h"
#include <bits/stdc++.h>
#define ll long long
#define db double
using namespace std;
db solve(int N, int M, int K, int H, vector <int> x, vector <int> y, vector <int> c, vector <int> P) {
K = min(K, 70);
vector <pair <int, db>> adj[N];
for (int i = 0; i < M; i++) adj[x[i]].emplace_back(y[i], c[i]), adj[y[i]].emplace_back(x[i], c[i]);
db dis[N][K + 1];
for (auto &E : dis) for (auto &e : E) e = DBL_MAX;
int vis[N]; memset(vis, 0, sizeof(vis));
queue <int> Q;
Q.emplace(0); vis[0] = 1;
while (!Q.empty()) {
int u = Q.front(); Q.pop();
if (u == H) continue;
for (auto [v, w] : adj[u]) if (!vis[v]) vis[v] = 1, Q.emplace(v);
}
memset(dis[0], 0, sizeof(dis[0]));
priority_queue <tuple <db, int, int>> q;
q.emplace(0, 0, 0);
for (int i = 1; i < N; i++) if (P[i] == 0 && vis[i]) memset(dis[i], 0, sizeof(dis[i])), q.emplace(0, i, 0);
while (!q.empty()) {
auto [W, u, k] = q.top();
q.pop();
W = -W;
if (dis[u][k] != W || u == H) continue;
for (auto [v, w] : adj[u]) {
if (dis[v][k] > dis[u][k] + w) q.emplace(-(dis[v][k] = dis[u][k] + w), v, k);
if (P[v] == 2 && k < K) if (dis[v][k+1] > (dis[u][k] + w) / 2) q.emplace(-(dis[v][k+1] = (dis[u][k] + w)/2), v, k+1);
}
}
db ans = DBL_MAX;
for (int i = 0; i <= K; i++) ans = min(ans, dis[H][i]);
return (ans == DBL_MAX ? -1 : ans);
}
