#include <bits/stdc++.h>
#include "cyberland.h"
// #include "stub.cpp"
using namespace std;
#define ff first
#define ss second
#define pii pair<int, int>
double solve(int n, int M, int K, int H, vector<int> x, vector<int> y, vector<int> c, vector<int> a) {
vector<pii> E[n];
for (int i = 0; i < M; i++) {
E[x[i]].push_back({y[i], c[i]});
E[y[i]].push_back({x[i], c[i]});
}
queue<int> q;
vector<bool> vis(n);
q.push(0); vis[0] = true;
while (!q.empty()) {
int x = q.front(); q.pop();
if (x == H) continue;
for (auto [i, w] : E[x]) {
if (!vis[i]) {
q.push(i);
vis[i] = true;
}
}
}
if (!vis[H]) return -1;
priority_queue<pair<double, pii>> pq;
vector<vector<double>> dis(n, vector<double>(K + 1, 1e18));
for (int i = 0; i < n; i++) {
if ((!i || !a[i]) && vis[i]) {
dis[i][0] = 0;
pq.push({0, {i, 0}});
}
}
while (!pq.empty()) {
auto [d, x] = pq.top(); d = -d; pq.pop();
if (x.ff == H || abs(d - dis[x.ff][x.ss]) > 1e-18) continue;
for (auto [i, w] : E[x.ff]) {
if (!i || !a[i]) continue;
double nd = d + w;
if (nd < dis[i][x.ss]) {
dis[i][x.ss] = nd;
pq.push({-nd, {i, x.ss}});
}
if (a[i] == 2 && x.ss < K && nd < 2 * dis[i][x.ss]) {
dis[i][x.ss + 1] = nd / 2;
pq.push({-(nd / 2), {i, x.ss + 1}});
}
}
}
return *min_element(dis[H].begin(), dis[H].end());
}
