Submission #1279734

#	Time	Username	Problem	Language	Result	Execution time	Memory
1279734		hanguyendanghuy	Commuter Pass (JOI18_commuter_pass)	C++20	100 / 100	221 ms	20272 KiB

commuter_pass

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define fi first
#define se second
constexpr ll MAXN=1e5+5,MAXV=3e5,MOD=1e9+7,INF=1e18;
ll n,m,i,j,p,k,ans,dem,st,en,dist[3][MAXN],S,T,U,V,len[MAXN],miV[MAXN],miU[MAXN];
vector<pair<ll,ll>> adj[MAXN];
void dij(ll st,ll type){
    priority_queue<pair<ll,ll>> q;
    dist[type][st]=0;
    q.push({0,st});
    while(q.size()){
        auto k=q.top();q.pop();
        if(-k.fi>dist[type][k.se]) continue;
        for(auto x:adj[k.se]){
            if(dist[type][x.fi]>-k.fi+x.se){
                dist[type][x.fi]=-k.fi+x.se;
                q.push({-dist[type][x.fi],x.fi});
            }
        }
    }
}
void solve(ll st,ll en){
    vector<ll> len(n + 1, INF);
    vector<ll> miU(n + 1, INF);
    vector<ll> miV(n + 1, INF);
    len[st]=0;
    miU[st]=dist[1][st];
    miV[st]=dist[2][st];
    priority_queue<pair<ll,int>, vector<pair<ll,int>>, greater<pair<ll,int>>> q;
    q.push({0, st});
    while (!q.empty()) {
        auto cur = q.top(); q.pop();
        ll curDist = cur.first;
        int u = cur.second;
        if (curDist > len[u]) continue; 

        for (auto &e : adj[u]) {
            int v = e.first;
            ll w = e.second;
            ll newDist = curDist + w;

            ll new_miU = min(miU[u], dist[1][v]);
            ll new_miV = min(miV[u], dist[2][v]);

            if (newDist < len[v]) {
                len[v] = newDist;
                miU[v] = new_miU;
                miV[v] = new_miV;
                q.push({len[v], v});
            } else if (newDist == len[v]) {
                if (new_miU + new_miV < miU[v] + miV[v]) {
                    miU[v] = new_miU;
                    miV[v] = new_miV;
                    q.push({len[v], v});
                }
            }
        }
    }
    if(len[en]!=INF){
        ans=min(ans,miU[en]+miV[en]);
    }
}
int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    cin>>n>>m>>S>>T>>U>>V;
    for(i=1;i<=m;i++){
        ll u,v,c;
        cin>>u>>v>>c;
        adj[u].pb({v,c});
        adj[v].pb({u,c});
    }
    for(i=1;i<=n;i++) dist[1][i]=dist[2][i]=INF;
    dij(U,1);
    dij(V,2);
    ans=dist[1][V];
    solve(S,T);
    solve(T,S);
    cout<<ans;
}

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