Submission #884746

#	Time	Username	Problem	Language	Result	Execution time	Memory
884746		tosivanmak	Commuter Pass (JOI18_commuter_pass)	C++17	0 / 100	205 ms	34072 KiB

commuter_pass

#include<bits/stdc++.h>
using namespace std;
#define ll long long

vector<pair<ll,ll> >adj[200005];
ll dist[200005];
ll fromu[200005],fromv[200005],cop[200005];
bool visited[200005];
priority_queue<pair<ll,ll> >q;
ll ans[200005];
ll stdist,uvdist;
void D(ll s){
    dist[s]=0;
    q.push({0,s});
    while(!q.empty()){
        pair<ll,ll>lol=q.top();
        q.pop();
        if(visited[lol.second]){
            continue;
        }
        visited[lol.second]=true;
        for(auto u: adj[lol.second]){
            if(dist[lol.second]+u.second<dist[u.first]){
                dist[u.first]=dist[lol.second]+u.second;
                q.push({-dist[u.first],u.first});
            }
        }
    }
}
void D2(ll s){
    dist[s]=0;
    q.push({0,s});
    while(!q.empty()){
        pair<ll,ll>lol=q.top();
        q.pop();
        if(visited[lol.second]){
            continue;
        }
        visited[lol.second]=true;
        for(auto u: adj[lol.second]){
            if(dist[lol.second]+u.second==dist[u.first]){
                ans[u.first]=min(ans[u.first],ans[lol.second]);
            }
            else if(dist[lol.second]+u.second<dist[u.first]){
                dist[u.first]=dist[lol.second]+u.second;
                ans[u.first]=ans[lol.second];
                q.push({-dist[u.first],u.first});
            }
        }
    }
}
int main(){
    ios::sync_with_stdio(false);
    cin.tie(NULL); cout.tie(NULL);
    ll n,m,s,t,u,v;
    cin>>n>>m>>s>>t>>u>>v;
    ll a[m+5],b[m+5],c[m+5];
    for(int i=1;i<=m;i++){
        cin>>a[i]>>b[i]>>c[i];
      adj[a[i]].push_back({b[i],c[i]});
      adj[b[i]].push_back({a[i],c[i]});
    }
    for(int i=1;i<=n;i++){
        dist[i]=1e10;
        visited[i]=false;
    }
    D(u);
    uvdist=dist[v];
    for(int i=1;i<=n;i++){
        fromu[i]=dist[i];
        dist[i]=1e10;
        visited[i]=false;
    }
    D(v);
    for(int i=1;i<=n;i++){
        fromv[i]=dist[i];
        dist[i]=1e10;
        visited[i]=false;
    }
    for(int i=1;i<=n;i++){
       ans[i]=fromu[i];
    }
    D2(s);
    stdist=dist[t];
    for(int i=1;i<=n;i++){
        cop[i]=dist[i];
        dist[i]=1e10;
        visited[i]=false;
    }
    D2(t);
    // cout<<uvdist<<'\n';
    for(int i=1;i<=n;i++){
        if(cop[i]+dist[i]==stdist){
            uvdist=min(uvdist,ans[i]+fromv[i]);
        }
    }
    cout<<uvdist<<'\n';
}

• Subtask 1: 0 / 16
• Subtask 2: 0 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 45