#include <bits/stdc++.h>
#include "cyberland.h"
using namespace std;
typedef long long ll;
const int N = 1e6 + 1;
vector<pair<int, int>> g[N];
int f, maxn;
double dijkstra(vector<int> &x)
{
double d[N];
for (int j = 0; j < maxn; j++)
{
d[j] = 1e15;
}
set<pair<double, int>> st;
for (int j : x)
{
d[j] = 0;
st.insert({d[j], j});
}
while (!st.empty())
{
int v = (*st.begin()).second;
st.erase({d[v], v});
for (auto [to, w] : g[v])
{
if (d[to] > d[v] + w)
{
st.erase({d[to], to});
d[to] = d[v] + w;
st.insert({d[to], to});
}
}
}
return d[f];
}
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> arr)
{
f = h;
maxn = n;
for (int i = 0; i < n; i++)
{
g[i].clear();
}
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]});
}
queue<int> q;
vector<int> can(n,0);
can[0] = 1;
q.push(0);
while(!q.empty()){
int v = q.front();
q.pop();
for(auto [to,w]:g[v]){
if(to == h || can[to]) continue;
q.push(to);
can[to] = 1;
}
}
vector<int> vv(1, 0);
double res = dijkstra(vv);
if (res == 1e15)
return -1;
vv.clear();
for (int j = 0; j < n; j++)
{
if (!arr[j] && can[j])
{
vv.push_back(j);
}
}
res = min(res,dijkstra(vv));
return res;
}
// int main() {
// int T;
// assert(1 == scanf("%d", &T));
// while (T--){
// int N,M,K,H;
// assert(4 == scanf("%d %d %d\n%d", &N, &M, &K, &H));
// std::vector<int> x(M);
// std::vector<int> y(M);
// std::vector<int> c(M);
// std::vector<int> arr(N);
// for (int i=0;i<N;i++)
// assert(1 == scanf("%d", &arr[i]));
// for (int i=0;i<M;i++)
// assert(3 == scanf("%d %d %d", &x[i], &y[i], &c[i]));
// printf("%.12lf\n", solve(N, M, K, H, x, y, c, arr));
// }
// }
