Submission #846596

#	Time	Username	Problem	Language	Result	Execution time	Memory
846596		damwuan	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	240 ms	35024 KiB

commuter_pass

#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define fi first
#define se second
#define for1(i,j,k) for(int i=j;i<=k;i++)
#define for2(i,j,k) for(int i=j;i>=k;i--)
#define for3(i,j,k,l) for(int i=j;i<=k;i+=l)
#define bit(n,i) ((n>>i)&1)
#define all(x) x.begin(),x.end()
//#pragma GCC optimize("O2,unroll-loops")
//#pragma GCC target("avx,avx2,bmi,bmi2,sse,sse2,sse3,ssse3,sse4,popcnt")
#define int long long
typedef long long ll;
typedef pair<int,int> pii;
typedef double ld;
typedef pair<ld,ld> pdd;
typedef pair<ll,ll> pll;
const ll maxn=2e5+5;
const ll offset=1e18;
const ll block_sz=317;
const ll inf=1e18;
const ll mod=1e9+7;
int n,u,v,s,t,m;
priority_queue<pii,vector<pii>,greater<pii>> pq;
vector<pii> adj1[maxn];
vector<int> adj[maxn];
vector<int> L;
int inu[maxn],inv[maxn],deg[maxn];
bool dd[maxn];
vector<int> disktra(int x)
{
    vector<int> dist(n+1,inf);
    dist[x]=0;
    pq.push({0,x});
    while (!pq.empty())
    {
        int u=pq.top().se;
        int _=pq.top().fi;
        pq.pop();
        if (dist[u]!=_) continue;
        for(auto [v,w]:adj1[u] )
        {
            if (dist[v]>dist[u]+w)
            {
                dist[v]=dist[u]+w;
                pq.push({dist[v],v});
            }
        }
    }
    return dist;

}
void sol()
{
    cin >> n>>m>>s>>t>>u>>v;
    for1(i,1,m)
    {
        int a,b,c;cin >>a>>b>>c;
        adj1[a].pb({b,c});
        adj1[b].pb({a,c});
    }
    vector<int> Lu=disktra(u);
    vector<int> Lv=disktra(v);
    vector<int> Ls=disktra(s);
    vector<int> Lt=disktra(t);
    for1(x,1,n)
    {
        if (Ls[x]+Lt[x]==Ls[t])
        {
//           cerr<< x<<'\n';
           dd[x]=true;
           inu[x]=Lu[x];
           inv[x]=Lv[x];
           for(auto [y,w]: adj1[x])
           {
               if (dd[y])
               {
                   if (Ls[y]+w==Ls[x])
                   {
                        deg[x]++;
                        adj[y].pb(x);
                   }
                   else if (Ls[y]==Ls[x]+w)
                   {
                       deg[y]++;
                       adj[x].pb(y);
                   }
               }
           }
        }
    }
//    for1(i,1,n)
//    {
//        if (dd[i])
//        {
//            if (!adj[i].empty())cerr<< i<< ' '<< adj[i][0]<<'\n';
//        }
//    }
    vector<int> qq;
    int ans=Lu[v];
    qq.pb(s);
    while(!qq.empty())
    {
        int x=qq.back();
        //cerr<< x<< '\n';
        qq.pop_back();
        ans=min(ans,min(inu[x]+Lv[x],inv[x]+Lu[x]));
        //cerr << ans<<'\n';
        for(int y:adj[x])
        {
            deg[y]--;
            inu[y]=min(inu[y],inu[x]);
            inv[y]=min(inv[y],inv[x]);
            if (deg[y]==0)
            {
                qq.pb(y);
            }
        }
    }
    cout << ans;

}


int32_t main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
//    freopen("GROUPDIV.inp","r",stdin);
//    freopen("GROUPDIV.out","w",stdout);

    int t=1;//cin >> t;
    while (t--)
    {
        sol();
    }
}
/*

3 1
12345678
?11
*/

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