# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
917580 | shenfe1 | Cyberland (APIO23_cyberland) | C++17 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
// #include "cyberland.h"
#pragma GCC optimize("Ofast")
#pragma GCC optimize("03")
#pragma GCC tartget("avx2")
using namespace std;
#define F first
#define S second
#define pb push_back
#define pii pair<int,int>
const int MAX=1e5+15;
const double inf=1e18;
double dp[MAX];
double solve(int n,int m,int k,int h,vector<int> x,vector<int> y,vector<int> c,vector<int> arr){
vector<pii> g[n+1];
for(int i=0;i<m;i++){
x[i]++;
y[i]++;
g[x[i]].pb({y[i],c[i]});
g[y[i]].pb({x[i],c[i]});
// cout<<x[i]<<" "<<y[i]<<" "<<c[i]<<"\n";
}
k=min(k,30);
h++;
for(int i=1;i<=n;i++){
dp[i]=inf;
}
dp[1]=0;
double ans=inf;
for(int i=0;i<=k;i++){
priority_queue<pair<double,int>> q;
for(int i=1;i<=n;i++){
if(dp[i]<inf)q.push({dp[i],i});
}
while(!q.empty()){
int v=q.top().S;
q.pop();
for(auto to:g[v]){
if(arr[to.F-1]==0&&dp[to.F]>0){
dp[to.F]=0;
q.push({dp[to.F],to.F});
}
if(dp[v]+to.S<dp[to.F]){
dp[to.F]=dp[v]+to.S;
q.push({dp[to.F],to.F});
}
}
}
for(int i=1;i<=n;i++){
if(arr[i-1]==2)dp[i]/=2;
}
ans=min(ans,dp[h]);
}
if(ans==inf)return -1.0;
return ans;
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int t;
cin>>t;
cout.precision(10);
while(t--){
int n,m,k,h;
cin>>n>>m>>k>>h;
vector<int> arr(n);
for(int i=0;i<n;i++)cin>>arr[i];
vector<int> x(m),y(m),c(m);
for(int i=0;i<m;i++)cin>>x[i]>>y[i]>>c[i];
cout<<fixed<<solve(n,m,k,h,x,y,c,arr)<<"\n";
}
}