#include <bits/stdc++.h>
using namespace std;
double solve(int N, int M, int K, int H, vector<int> x, vector<int> y, vector<int> c, vector<int> arr) {
const double INF = numeric_limits<double>::infinity();
vector<vector<pair<int, double>>> graph(N);
for (int i = 0; i < M; ++i) {
graph[x[i]].emplace_back(y[i], c[i]);
graph[y[i]].emplace_back(x[i], c[i]);
}
vector<vector<double>> dist(N, vector<double>(K + 1, INF));
dist[0][K] = 0.0;
priority_queue<tuple<double, int, int>, vector<tuple<double, int, int>>, greater<>> pq;
pq.emplace(0.0, 0, K);
while (!pq.empty()) {
auto [current_time, current_country, remaining_divides] = pq.top();
pq.pop();
if (current_country == H) {
return current_time;
}
if (current_time > dist[current_country][remaining_divides]) {
continue;
}
for (const auto& [next_country, travel_time] : graph[current_country]) {
double new_time = current_time + travel_time;
if (arr[next_country] == 0) {
new_time = 0.0;
}
if (new_time < dist[next_country][remaining_divides]) {
dist[next_country][remaining_divides] = new_time;
pq.emplace(new_time, next_country, remaining_divides);
}
if (arr[next_country] == 2 && remaining_divides > 0) {
double divided_time = new_time / 2.0;
if (divided_time < dist[next_country][remaining_divides - 1]) {
dist[next_country][remaining_divides - 1] = divided_time;
pq.emplace(divided_time, next_country, remaining_divides - 1);
}
}
}
}
return -1.0;
}
