Submission #1082693

#	Time	Username	Problem	Language	Result	Execution time	Memory
1082693		lftroq	Commuter Pass (JOI18_commuter_pass)	C++14	100 / 100	323 ms	52168 KiB

commuter_pass

#include<bits/stdc++.h>
#define endl '\n'
#define fi first
#define se second
using namespace std;
typedef long long ll;

const int N=1e5+5;
const ll INF=1e15;

int n,m,s,t,x,y;
vector<pair<int,int>> graph[N],g[4*N];
ll d[2][N],d1[4*N];

void dijkstra(int s,int k)
{
    for(int i=1;i<=n;i++) d[k][i]=INF;
    d[k][s]=0;
    priority_queue<pair<ll,pair<int,int>>,vector<pair<ll,pair<int,int>>>,greater<pair<ll,pair<int,int>>>> pq;
    pq.push({d[k][s],{k,s}});
    while((int)pq.size())
    {
        ll temp=pq.top().fi;
        int k=pq.top().se.fi,u=pq.top().se.se;
        pq.pop();
        if(temp!=d[k][u]) continue;
        for(int i=0;i<(int)graph[u].size();i++)
        {
            int v=graph[u][i].fi,w=graph[u][i].se;
            if(d[k][v]>d[k][u]+w)
            {
                d[k][v]=d[k][u]+w;
                pq.push({d[k][v],{k,v}});
            }
        }
    }
}

void solve()
{
    cin >> n >> m >> s >> t >> x >> y;
    for(int i=1;i<=m;i++)
    {
        int u,v,w;
        cin >> u >> v >> w;
        graph[u].push_back({v,w});
        graph[v].push_back({u,w});
    }
    dijkstra(s,0);dijkstra(t,1);
    for(int u=1;u<=n;u++)
    {
        g[u].push_back({n+u,0});
        g[u].push_back({2*n+u,0});
        g[n+u].push_back({3*n+u,0});
        g[2*n+u].push_back({3*n+u,0});
        for(int i=0;i<(int)graph[u].size();i++)
        {
            int v=graph[u][i].fi,w=graph[u][i].se;
            if(d[0][u]+w+d[1][v]==d[0][t])
            {
                g[n+u].push_back({n+v,0});
                g[2*n+v].push_back({2*n+u,0});
            }
            g[u].push_back({v,w});g[3*n+u].push_back({3*n+v,w});
        }
    }
    priority_queue<pair<ll,int>,vector<pair<ll,int>>,greater<pair<ll,int>>> pq;
    for(int i=1;i<=4*n;i++) d1[i]=INF;
    d1[x]=0;
    pq.push({d1[x],x});
    while((int)pq.size())
    {
        ll temp=pq.top().fi;
        int u=pq.top().se;
        pq.pop();
        if(temp!=d1[u]) continue;
        for(int i=0;i<(int)g[u].size();i++)
        {
            int v=g[u][i].fi,w=g[u][i].se;
            if(d1[v]>d1[u]+w)
            {
                d1[v]=d1[u]+w;
                pq.push({d1[v],v});
            }
        }
    }
    cout << d1[3*n+y] << endl;
}

int main()
{
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    //freopen("hanhhhh.inp","r",stdin);
    //freopen("hanhhhh.out","w",stdout);
    int t=1;
    //cin >> t;
    while(t--)
    solve();
    return 0;
}

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