Submission #47137

#	Time	Username	Problem	Language	Result	Execution time	Memory
47137		dqhungdl	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	705 ms	156224 KiB

commuter_pass

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

typedef pair<int64_t,int64_t> ii;
typedef pair<ii,int64_t> iii;
int64_t n,m,S,T,U,V,res,d[100005],dS[100005],dT[100005],dU[100005],dV[100005],F1[100005],F2[100005];
bool Free[100005];
vector<int64_t> dag[100005];
vector<ii> g[100005];
vector<iii> Edge;
set<ii> s;

void Dijkstra(int64_t start)
{
    for(int64_t i=1; i<=n; i++)
        d[i]=1e15;
    d[start]=0;
    s.insert(ii(0,start));
    while(s.size()>0)
    {
        int64_t u=(*s.begin()).second;
        s.erase(s.begin());
        for(int64_t i=0; i<g[u].size(); i++)
        {
            int64_t v=g[u][i].first;
            int64_t w=g[u][i].second;
            if(d[v]>d[u]+w)
            {
                if(d[v]!=1e15)
                    s.erase(s.find(ii(d[v],v)));
                d[v]=d[u]+w;
                s.insert(ii(d[v],v));
            }
        }
    }
}

void DFS(int64_t u)
{
    Free[u]=true;
    F1[u]=dV[u];
    F2[u]=dU[u];
    for(int64_t i=0; i<dag[u].size(); i++)
    {
        int64_t v=dag[u][i];
        if(Free[v]==false)
            DFS(v);
        F1[u]=min(F1[u],F1[v]);
        F2[u]=min(F2[u],F2[v]);
    }
    res=min(res,min(dU[u]+F1[u],dV[u]+F2[u]));
}

int main()
{
    ios_base::sync_with_stdio(false);
    //freopen("TEST.INP","r",stdin);
    cin>>n>>m>>S>>T>>U>>V;
    int64_t u,v,w;
    while(m--)
    {
        cin>>u>>v>>w;
        Edge.push_back(iii(ii(u,v),w));
        g[u].push_back(ii(v,w));
        g[v].push_back(ii(u,w));
    }
    Dijkstra(S);
    for(int64_t i=1; i<=n; i++)
        dS[i]=d[i];
    Dijkstra(T);
    for(int64_t i=1; i<=n; i++)
        dT[i]=d[i];
    Dijkstra(U);
    for(int64_t i=1; i<=n; i++)
        dU[i]=d[i];
    Dijkstra(V);
    for(int64_t i=1; i<=n; i++)
        dV[i]=d[i];
    for(int64_t i=0; i<Edge.size(); i++)
    {
        int64_t u=Edge[i].first.first;
        int64_t v=Edge[i].first.second;
        int64_t w=Edge[i].second;
        if(dS[u]+dT[v]+w==dS[T])
            dag[u].push_back(v);
        if(dS[v]+dT[u]+w==dS[T])
            dag[v].push_back(u);
    }
    res=dU[V];
    DFS(S);
    cout<<res;
}

Compilation message (stderr)

commuter_pass.cpp: In function 'void Dijkstra(int64_t)':
commuter_pass.cpp:23:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int64_t i=0; i<g[u].size(); i++)
                          ~^~~~~~~~~~~~
commuter_pass.cpp: In function 'void DFS(int64_t)':
commuter_pass.cpp:43:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int64_t i=0; i<dag[u].size(); i++)
                      ~^~~~~~~~~~~~~~
commuter_pass.cpp: In function 'int main()':
commuter_pass.cpp:79:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int64_t i=0; i<Edge.size(); i++)
                      ~^~~~~~~~~~~~

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