#include "bits/stdc++.h"
#include "cyberland.h"
using namespace std;
const char nl = '\n';
#include <vector>
double solve(int N, int M, int K, int H, vector<int> x, vector<int> y, vector<int> c, vector<int> arr) {
K = min(K, 70);
vector<pair<int, double>> adj[N];
for(int i = 0; i < M; ++i) {
adj[x[i]].emplace_back(y[i], c[i]);
adj[y[i]].emplace_back(x[i], c[i]);
}
/* cout << N << " cities" << nl; */
/* cout << M << " edges" << nl; */
/* cout << H << " destination" << nl; */
/* for(int i = 0; i < M; ++i) { */
/* cout << i << " : "; */
/* for(auto u : adj[i]) { */
/* cout << "(" << u.first << ", " << u.second << ") "; */
/* } */
/* cout << nl; */
/* } */
double dist[N][K + 1];
for(int i = 0; i < N; ++i) {
for(int j = 0; j <= K; ++j) {
dist[i][j] = -1;
}
}
priority_queue<pair<double, pair<int, int>>> pq;
dist[0][0] = 0;
pq.push({-dist[0][0], {0, 0}});
while(!pq.empty()) {
int a = pq.top().second.second;
int st = -pq.top().second.first;
double d = -pq.top().first;
pq.pop();
if(dist[a][st] < d || a == H) {
continue;
}
for(auto [b, w] : adj[a]) {
if(arr[b] == 0) {
dist[b][st] = 0;
pq.push({-dist[b][st], {-st, b}});
continue;
}
if(dist[b][st] == -1 || d + w < dist[b][st]) {
dist[b][st] = d + w;
pq.push({-dist[b][st], {-st, b}});
}
if(arr[b] == 2 && st < K) {
++st;
if(dist[b][st] == -1 || (d + w) / 2 < dist[b][st]) {
dist[b][st] = (d + w) / 2;
pq.push({-dist[b][st], {-st, b}});
}
--st;
}
}
}
double ans = -1;
for(int i = 0; i <= K; ++i) {
if(ans == -1 || (dist[H][i] != -1 && ans > dist[H][i]))
ans = dist[H][i];
}
return ans;
}
