Submission #783522

#	Time	Username	Problem	Language	Result	Execution time	Memory
783522		8pete8	Commuter Pass (JOI18_commuter_pass)	C++14	100 / 100	217 ms	25704 KiB

commuter_pass

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define f first
#define s second
#define pb push_back
#define p push
#define pii pair<int,int>
#define ppii pair<int,pii>
#define fastio ios::sync_with_stdio(false);cin.tie(NULL);
#define set(x) memset(x,-1,sizeof(x));
int n,m,s,t,u,v;
#define int long long
const int mxn=1e5,inf=LONG_LONG_MAX/2;
vector<pii>adj[mxn+10];
bitset<mxn+10>vis;
void dijk(int st,vector<int>&dist){
    priority_queue<pii,vector<pii>,greater<pii>>pq;
    pq.p({0,st});
    dist[st]=0;
    while(!pq.empty()){
        int cur=pq.top().s;
        pq.pop();
        if(vis[cur])continue;
        vis[cur]=true;
        for(auto i:adj[cur]){
            if(dist[i.f]>dist[cur]+i.s)dist[i.f]=dist[cur]+i.s,pq.p({dist[i.f],i.f});
        }
    }
    vis.reset();
}
int32_t main(){
    fastio
    cin>>n>>m>>s>>t>>u>>v;
    while(m--){
        int a,b,c;cin>>a>>b>>c;
        adj[a].pb({b,c});
        adj[b].pb({a,c});
    }
    vector<int>dist1(n+1,inf);
    vector<int>dist2(n+1,inf);
    dijk(u,dist1);
    dijk(v,dist2);
    priority_queue<ppii,vector<ppii>,greater<ppii>>pq;
    //dist cur pa
    pq.p({0,{s,0}});
    vector<pair<int,pii>>dist(n+1,{inf,{inf,inf}});
    dist[s].f=0;
    while(!pq.empty()){
        int cur=pq.top().s.f,pa=pq.top().s.s,cd=pq.top().f;
        pq.pop();
        if(vis[cur]){
            if(cd==dist[cur].f){
                int cnu=min(dist1[cur],dist[pa].s.f),cnv=min(dist2[cur],dist[pa].s.s);
                if(cnu+cnv<=dist[cur].s.f+dist[cur].s.s){
                    dist[cur].s.f=cnu;
                    dist[cur].s.s=cnv;
                }
            }
            continue;
        }
        vis[cur]=true;
        dist[cur].s.f=min(dist1[cur],dist[pa].s.f);
        dist[cur].s.s=min(dist2[cur],dist[pa].s.s);
        for(auto i:adj[cur]){
            if(dist[i.f].f==-1||dist[i.f].f>=dist[cur].f+i.s){
                int ndu=min(dist[cur].s.f,dist1[i.f]),ndv=min(dist[cur].s.s,dist2[i.f]);
                dist[i.f]={dist[cur].f+i.s,{ndu,ndv}};
                pq.p({dist[i.f].f,{i.f,cur}});
            }
        }
    }
    cout<<min(dist[t].s.f+dist[t].s.s,dist1[v]);
}

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