#include <bits/stdc++.h>
using namespace std;
#define F first
#define S second
using ll = long long;
const double INF = 1e16 + 7;
vector<vector<pair<int, double>>> adj;
vector<bool> vis;
void dfs(int k, int& H) {
if (k == H || vis[k])
return;
vis[k] = true;
for (auto& i : adj[k])
dfs(i.F, H);
}
double solve(int N, int M, int K, int H, vector<int> x, vector<int> y, vector<int> c, vector<int> arr) {
adj.resize(N);
vis.resize(N, false);
for (int i = 0; i < M; i++) {
adj[x[i]].emplace_back(y[i], (double)c[i]);
adj[y[i]].emplace_back(x[i], (double)c[i]);
}
dfs(0, H);
vector<vector<double>> dist(K + 1, vector<double>(N, INF));
for (int i = 0; i < N; i++) {
if (arr[i] == 0 && vis[i]) {
for (int j = 0; j <= K; j++) {
dist[j][i] = 0;
}
}
}
for (int i = 0; i <= K; i++) {
priority_queue<pair<double, int>, vector<pair<double, int>>, greater<pair<double, int>>> PQ;
dist[i][0] = 0;
for (int j = 0; j < N; j++) {
if (dist[i][j] == 0) {
PQ.emplace(0, j);
}
}
while (!PQ.empty()) {
int u;
double d;
tie(d, u) = PQ.top();
PQ.pop();
if (d != dist[i][u] || u == H)
continue;
for (auto& k : adj[u]) {
int v;
double w;
tie(v, w) = k;
bool flag = false;
if (dist[i][v] > dist[i][u] + w) {
dist[i][v] = dist[i][u] + w;
flag = true;
}
if (i > 0 && arr[v] == 2 && dist[i][v] > (dist[i - 1][u] + w) / 2.0) {
dist[i][v] = (dist[i - 1][u] + w) / 2.0;
flag = true;
}
if (flag)
PQ.emplace(dist[i][v], v);
}
}
}
return (dist[K][H] == INF ? -1 : dist[K][H]);
}
