#include <bits/stdc++.h>
#include "cyberland.h"
using namespace std;
constexpr double inf = 1e18;
vector<vector<pair<int, int>>> g;
vector<double> get(int t, int n, int skip) {
priority_queue<pair<double, int>, vector<pair<double, int>>, greater<pair<double, int>>> pq;
vector<double> d(n, inf);
d[t] = 0;
pq.push({0, t});
while (!pq.empty()) {
auto [k, u] = pq.top();
pq.pop();
if (k > d[u]) continue;
for (auto [v, w] : g[u]) {
if (v == skip) continue;
if (d[v] > k + w) {
d[v] = k + w;
pq.push({d[v], v});
}
}
}
return d;
}
double solve(int n, int m, int k, int h, vector<int> x, vector<int> y, vector<int> c, vector<int> arr) {
g.assign(n, {});
for (int i = 0; i < m; i++) {
g[x[i]].push_back({y[i], c[i]});
g[y[i]].push_back({x[i], c[i]});
}
vector<double> t = get(0, n, -1);
vector<double> d = get(h, n, 0);
vector<double> s = get(0, n, h);
if (t[h] == inf) {
return -1;
}
double mn = t[h];
int pos = 0;
for (int i = 0; i < n; i++) {
if (arr[i] == 0 && s[i] != inf) {
if (d[i] < mn) {
mn = d[i];
pos = i;
}
}
}
double chk = 0;
for (int i = pos; i < h; i++) {
chk += c[i];
}
assert(chk == mn);
int left = 0;
for (int i = pos + 1; i <= h; i++) {
if (arr[i] == 2) {
left++;
}
}
double ans = 0;
for (int i = pos; i < h; i++) {
ans += c[i];
if (arr[i + 1] == 2) {
if (left == 2 && k % 2 == 0) {
ans /= 2;
k--;
}
if (left == 1) {
k--;
for (int j = 0; j + 2 < k; j += 2) {
ans /= 2;
ans += c[i];
ans /= 2;
ans += c[i];
}
ans /= 2;
}
left--;
}
}
return ans;
}
