Submission #1181251

#	Time	Username	Problem	Language	Result	Execution time	Memory
1181251		Godgift42	Commuter Pass (JOI18_commuter_pass)	C++20	31 / 100	541 ms	21220 KiB

commuter_pass

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

using ll = long long;

int main(){
    //ios_base::sync_with_stdio(0);
    //cin.tie(0);
    int n,m;
    cin >> n >> m;
    int s,t,u,v;
    cin >> s >> t >> u >> v;
    s--;t--;u--;v--;
    vector<vector<pair<int,ll>>> adj(n);
    for(int i=0;i<m;i++){
        int a,b;
        ll c;
        cin >> a >> b >> c;
        a--;b--;
        adj[a].push_back({b,c});
        adj[b].push_back({a,c});
    }
    vector<ll> du(n,10000000000000000);
    vector<ll> dv(n,10000000000000000);
    vector<bool> vis(n);
    priority_queue<pair<ll,int>> pq;
    du[u]=0;
    pq.push({0,u});
    while(!pq.empty()){
        int cr=pq.top().second;
        pq.pop();
        if(!vis[cr]){
            vis[cr]=true;
            for(auto [ch,w]:adj[cr]){
                if(!vis[ch] and du[ch]>du[cr]+w){
                    du[ch]=du[cr]+w;
                    pq.push({-du[ch],ch});
                }
            }
        }
    }
    
    for(int i=0;i<n;i++)vis[i]=false;
    dv[v]=0;
    pq.push({0,v});
    while(!pq.empty()){
        int cr=pq.top().second;
        pq.pop();
        if(!vis[cr]){
            vis[cr]=true;
            for(auto [ch,w]:adj[cr]){
                if(!vis[ch] and dv[ch]>dv[cr]+w){
                    dv[ch]=dv[cr]+w;
                    pq.push({-dv[ch],ch});
                }
            }
        }
    }
    ll ans=du[v];
    for(int i=0;i<n;i++)vis[i]=false;
    vector<vector<ll>> dp(2,vector<ll>(n,1000000000000000000));
    vector<ll> dist(n,1000000000000000000);
    priority_queue<pair<ll,pair<int,int>>> qp;
    qp.push({0,{s,s}});
    dist[s]=0;
    dp[0][s]=du[s];
    dp[1][s]=dv[s];
    while(!qp.empty()){
        int node=qp.top().second.first;
        int par=qp.top().second.second;
        ll cd=qp.top().first;
        qp.pop();
        if(!vis[node]){
            vis[node]=true;
            dp[0][node]=min(du[node],min(dp[0][par],dp[0][node]));
            dp[1][node]=min(dv[node],min(dp[1][par],dp[1][node]));
            for(auto [ch,w]:adj[node]){
                if(dist[ch]>=dist[node]+w){
                    dist[ch]=dist[node]+w;
                    qp.push({-dist[ch],{ch,node}});
                }
            }
        }   
        else if(-cd==dist[node]){
            dp[0][node]=min(du[node],min(dp[0][par],dp[0][node]));
            dp[1][node]=min(dv[node],min(dp[1][par],dp[1][node]));
        }
    }
    ans=min(ans,dp[0][t]+dp[1][t]);
    for(int i=0;i<n;i++){
        dist[i]=1000000000000000000;
        vis[i]=false;
        dp[0][i]=1000000000000000000;
        dp[1][i]=1000000000000000000;
    }
    dist[t]=0;
    qp.push({0,{t,t}});
    dp[0][t]=du[t];
    dp[1][t]=dv[t];
    while(!qp.empty()){
        int node=qp.top().second.first;
        int par=qp.top().second.second;
        ll cd=qp.top().first;
        qp.pop();
        if(!vis[node]){
            vis[node]=true;
            dp[0][node]=min(du[node],min(dp[0][par],dp[0][node]));
            dp[1][node]=min(dv[node],min(dp[1][par],dp[1][node]));
            for(auto [ch,w]:adj[node]){
                if(dist[ch]>=dist[node]+w){
                    dist[ch]=dist[node]+w;
                    qp.push({-dist[ch],{ch,node}});
                }
            }
        }   
        else if(-cd==dist[node]){
            dp[0][node]=min(du[node],min(dp[0][par],dp[0][node]));
            dp[1][node]=min(dv[node],min(dp[1][par],dp[1][node]));
        }
    }
    ans=min(ans,dp[0][s]+dp[1][s]);
    cout << ans << "\n";
}

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