Submission #1167220

#	Time	Username	Problem	Language	Result	Execution time	Memory
1167220		Valters07	Commuter Pass (JOI18_commuter_pass)	C++20	100 / 100	283 ms	20836 KiB

commuter_pass

#include <bits/stdc++.h>
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,popcnt,lzcnt")
#define fio ios_base::sync_with_stdio(0);cin.tie(0);
#define ll long long
#define ld long double
#define en exit(0);
#define pb push_back
#define fi first
#define se second
using namespace std;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int N = 1e5+5;
const ll INF = 1e18+5;
vector<pair<int,int> > g[N];
vector<int> g_opt[N];
bool mark[N];
ll minU[N], minV[N];
vector<ll> dijkstra(int st, int n)
{
    vector<ll> dist(n+1,INF);
    vector<bool> vis(n+1);
    priority_queue<pair<ll,int> > q;
    dist[st]=0;
    q.push({0,st});
    while(!q.empty())
    {
        int u = q.top().se;
        q.pop();
        if(vis[u])
            continue;
        vis[u]=1;
        for(auto [v,w]:g[u])
        {
            ll nwd = dist[u]+w;
            if(nwd<dist[v])
            {
                dist[v]=nwd;
                q.push({-nwd,v});
            }
        }
    }
    return dist;
}
int main()
{
    fio
//    ifstream cin("in.in");
    int n, m, S, T, U, V;
    cin >> n >> m >> S >> T >> U >> V;
    while(m--)
    {
        int u, v, w;
        cin >> u >> v >> w;
        g[u].pb({v,w});
        g[v].pb({u,w});
    }
    vector<ll> dS = dijkstra(S,n);
    vector<ll> dT = dijkstra(T,n);
    vector<ll> dU = dijkstra(U,n);
    vector<ll> dV = dijkstra(V,n);
    ll mincost = dS[T];
    for(int i = 1;i<=n;i++)
        if(dS[i]+dT[i]==mincost)
            mark[i]=1;
    for(int u = 1;u<=n;u++)
        for(auto [v,w]:g[u])
            if(mark[u]&&mark[v]&&dS[v]==dS[u]+w)
                g_opt[u].pb(v);
    vector<pair<ll,int> > vert;
    for(int i = 1;i<=n;i++)
        if(mark[i])
            vert.pb({dS[i],i});
    sort(vert.begin(),vert.end(),greater<pair<ll,int> >());
    ll res = INF;
    for(auto [d,x]:vert)
    {
        minU[x] = dU[x];
        minV[x] = dV[x];
        for(auto y:g_opt[x])
        {
            minU[x]=min(minU[x],minU[y]);
            minV[x]=min(minV[x],minV[y]);
        }
        res = min(res,dU[x]+minV[x]);
        res = min(res,dV[x]+minU[x]);
    }
    res = min(res,dU[V]);
    cout << res;
    return 0;
}

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