#include "cyberland.h"
#include <bits/stdc++.h>
using namespace std;
const double eps = 1e-7;
const int MAX = 100005;
vector<pair<int, int>> g[MAX];
double dist[MAX * 68];
double lst[MAX * 68];
double solve(int n, int m, int k, int h, std::vector<int> x, std::vector<int> y, std::vector<int> c, std::vector<int> a) {
k = min(k, 66);
for (int i = 0; i < n; i++) {
g[i].clear();
}
for (int i = 0; i < m; i++) {
g[x[i]].emplace_back(y[i], c[i]);
g[y[i]].emplace_back(x[i], c[i]);
}
vector<int> que(1, 0);
vector<bool> was(n, false);
was[0] = true;
for (int b = 0; b < (int) que.size(); b++) {
int i = que[b];
for (auto& p : g[i]) {
int j = p.first;
if (j == h) {
was[j] = true;
}
if (!was[j]) {
was[j] = true;
que.push_back(j);
}
}
}
if (!was[h]) {
return -1;
}
const double inf = 1e15;
k += 1;
que.push_back(h);
for (int i : que) {
for (int j = 0; j < k; j++) {
dist[i * k + j] = inf;
lst[i * k + j] = inf;
}
}
priority_queue<pair<int, pair<double, int>>> pq;
for (int j : que) {
if (j == 0 || a[j] == 0) {
dist[j * k] = 0;
pq.push({0, {dist[j * k], j * k}});
}
}
double ans = inf;
while (!pq.empty()) {
auto it = pq.top();
int v = it.second.second;
pq.pop();
int i = v / k;
int j = v % k;
if (i == h) {
ans = min(ans, dist[v]);
if (ans <= eps) {
return ans;
}
continue;
}
if (lst[v] <= dist[v] + eps) {
continue;
}
lst[v] = dist[v];
for (auto& p : g[i]) {
int to = p.first;
int w = p.second;
if (to == 0 || a[to] == 0) {
continue;
}
if (dist[to * k + j] > dist[v] + w + eps) {
int nto = to * k + j;
dist[nto] = dist[v] + w;
pq.push({-j, {-dist[nto], nto}});
}
if (a[to] == 2) {
if (j + 1 < k && dist[to * k + j + 1] > (dist[v] + w) / 2.000000 + eps) {
int nto = to * k + j + 1;
dist[nto] = (dist[v] + w) / 2.000000;
pq.push({-(j + 1), {-dist[nto], nto}});
}
}
}
}
if (ans == inf) {
ans = -1;
}
return ans;
}
/*
1
3 2 30
2
1 2 1
1 2 12
2 0 4
4.00000000000
1
4 4 30
3
1 0 2 1
0 1 5
0 2 4
1 3 2
2 3 4
2.00000000000
*/
