Submission #563126

#	Time	Username	Problem	Language	Result	Execution time	Memory
563126		jk410	Commuter Pass (JOI18_commuter_pass)	C++17	15 / 100	2059 ms	262144 KiB

commuter_pass

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll INF=4e18;
struct edge{
    int v;
    ll cost;
    bool operator<(const edge &tmp)const{
        return cost>tmp.cost;
    }
};
int N,M,S,T,U,V;
vector<edge> Edge[100001];
vector<int> To[100001],From[100001];
ll Dist[100001],Dist_U[100001],Dist_V[100001],Min_U[100001],Min_V[100001];
bool Visited[100001];
queue<int> Q;
ll Ans;
void dijkstra(int st,ll *dist){
    for (int i=1; i<=N; i++)
        dist[i]=INF;
    dist[st]=0;
    priority_queue<edge> q;
    q.push({st,0});
    while (!q.empty()){
        edge t=q.top();
        q.pop();
        if (dist[t.v]<t.cost)
            continue;
        for (edge i:Edge[t.v]){
            if (dist[i.v]>t.cost+i.cost){
                dist[i.v]=t.cost+i.cost;
                q.push({i.v,dist[i.v]});
            }
        }
    }
}
int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cin>>N>>M>>S>>T>>U>>V;
    while (M--){
        int a,b,c;
        cin>>a>>b>>c;
        Edge[a].push_back({b,c});
        Edge[b].push_back({a,c});
    }
    dijkstra(S,Dist);
    dijkstra(U,Dist_U);
    dijkstra(V,Dist_V);
    Q.push(T);
    while (!Q.empty()){
        int v=Q.front();
        Q.pop();
        for (edge i:Edge[v]){
            if (Dist[v]==Dist[i.v]+i.cost){
                To[i.v].push_back(v);
                From[v].push_back(i.v);
                Q.push(i.v);
            }
        }
    }
    Min_U[0]=Min_V[0]=Dist_U[0]=Dist_V[0]=INF;
    From[S].push_back(0);
    Ans=Dist_U[V];
    Q.push(S);
    while (!Q.empty()){
        int v=Q.front();
        Q.pop();
        if (Visited[v])
            continue;
        Visited[v]=true;
        Min_U[v]=Min_V[v]=INF;
        for (int i:From[v]){
            Min_U[v]=min({Min_U[v],Min_U[i],Dist_U[i]});
            Min_V[v]=min({Min_V[v],Min_V[i],Dist_V[i]});
        }
        Ans=min({Ans,Min_U[v]+Dist_V[v],Min_V[v]+Dist_U[v]});
        for (int i:To[v])
            Q.push(i);
    }
    cout<<Ans;
    return 0;
}

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