Submission #680695

#	Time	Username	Problem	Language	Result	Execution time	Memory
680695		kakayoshi	Commuter Pass (JOI18_commuter_pass)	C++14	100 / 100	506 ms	37008 KiB

commuter_pass

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

#define forw(i,a,b) for(ll i=a;i<=b;i++)
#define forb(i,a,b) for(ll i=a;i>=b;i--)
#define pu push
#define pb push_back
#define fi first
#define se second
#define all(a) a.begin(),a.end()
#define minimize(a,b) a=min(a,b)
#define maximize(a,b) a=max(a,b)
typedef long long int ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef pair<ll,pair<ll,ll> > plll;
const int maxN=2e5+5;
const ll oo=1e18;
ll n,m,U,V,s,t,d[maxN][4],dp[maxN][2],father[maxN];
vector <pll> edge[maxN];
vector <ll> new_edge[maxN];
vector <plll> pend;
void dijk(int s, int id)
{
    forw(i,1,n) d[i][id]=oo;
    d[s][id]=0;
    priority_queue<pll, vector <pll> , greater<pll> > p;
    p.pu({0,s});
    while (p.size())
    {
        ll u=p.top().se;
        ll val=p.top().fi;
        p.pop();
        if (val>d[u][id]) continue;
        for(auto tmp:edge[u])
        {
            ll v=tmp.se;
            ll add=tmp.fi;
            if (val+add<d[v][id])
            {
                d[v][id]=val+add;
                p.pu({d[v][id],v});
            }
        }
    }
    return;
}
void solve()
{
    cin>>n>>m;
    cin>>s>>t>>U>>V;
    forw(i,1,m)
    {
        ll u,v,z; cin>>u>>v>>z;
        edge[u].pb({z,v});
        edge[v].pb({z,u});
        pend.pb({z,{u,v}});
    }
    dijk(s,0);
    dijk(t,1);
    dijk(U,2);
    dijk(V,3);
    for(auto tmp:pend)
    {
        ll val=tmp.fi; ll u=tmp.se.fi; ll v=tmp.se.se;
        if (d[u][0]+val+d[v][1]==d[t][0])
        {
            father[v]++;
            new_edge[u].pb(v);
        }
        if (d[v][0]+val+d[u][1]==d[t][0])
        {
            father[u]++;
            new_edge[v].pb(u);
        }
    }
    ll ans=d[V][2];
    forw(i,1,n)
    {
        dp[i][0]=d[i][2]; // from U
        dp[i][1]=d[i][3]; // from V
    }
    queue<ll> p;
    p.pu(s);
    while (p.size())
    {
        ll u=p.front(); p.pop();
        ans=min(ans,dp[u][0]+d[u][3]); // to V
        ans=min(ans,dp[u][1]+d[u][2]); // to U
        for(int v:new_edge[u])
        {
            dp[v][0]=min(dp[v][0],dp[u][0]);
            dp[v][1]=min(dp[v][1],dp[u][1]);
            if (--father[v]==0) p.pu(v);
        }
    }
    cout<<ans;
    return;
}
int main()
{
    ios::sync_with_stdio();
    cin.tie(0);
    //freopen("bruh.inp","r",stdin);
    //freopen("bruh.out","w",stdout);
    solve();
    return 0;
}

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