#include "bits/stdc++.h"
#include "cyberland.h"
using namespace std;
#include <vector>
void bfs(int N, int M, int K, int H, vector<int> x, vector<int> y, vector<int> c, vector<int> arr, vector<pair<int, double>> adj[], double dist[]) {
bool vis[N] = {};
queue<int> qu;
vis[0] = 1;
qu.push(0);
dist[0] = 0;
while(!qu.empty()) {
int a = qu.front();
qu.pop();
if(a == H) continue;
for(auto [b, w] : adj[a]) {
if(vis[b]) continue;
vis[b] = 1;
qu.push(b);
if(arr[b] == 0) dist[b] = 0;
}
}
}
double solve(int N, int M, int K, int H, vector<int> x, vector<int> y, vector<int> c, vector<int> arr) {
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]);
}
double dist[N];
for(int i = 0; i < N; ++i) dist[i] = -1;
bfs(N, M, K, H, x, y, c, arr, adj, dist);
priority_queue<pair<double, int>> pq;
for(int i = 0; i < N; ++i) {
if(dist[i] == 0 || i == 0) {
dist[i] = 0;
pq.emplace(-dist[i], i);
}
}
while(!pq.empty()) {
int a = pq.top().second;
double d = -pq.top().first;
pq.pop();
if(dist[a] < d || a == H) {
continue;
}
for(auto [b, w] : adj[a]) {
if(dist[b] == -1 || d + w < dist[b]) {
dist[b] = d + w;
pq.emplace(-dist[b], b);
}
}
}
return dist[H];
}
