제출 #854197

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
854197		LeVanThuc	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	409 ms	50412 KiB

commuter_pass

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define fi first
#define se second
#define p(x,y) pair<ll,ll>(x,y)
#define BIT(i,x) ((x>>i)&1)
#define MASK(x) (1<<x)
#define ld long double
#define __builtin_popcount __builtin_popcountll
#define pll pair<ll,ll>
template<class T1,class T2>
bool maximize(T1 &x,const T2 &y)
{
    if(x<y)
    {
        x=y;
        return 1;
    }
    return 0;
}
template<class T1,class T2>
bool minimize(T1 &x,const T2 &y)
{
    if(x>y)
    {
        x=y;
        return 1;
    }
    return 0;
}
void online()
{
    std::ios_base::sync_with_stdio(0);
    cin.tie(0);
#ifdef thuc
    freopen("input.INP","r",stdin);
    freopen("output.OUT","w",stdout);
#endif
}
const ll N=2e5+10,inf=1e18;
ll dists[N],distt[N],n,m,f[N][4],U[N],V[N],C[N];
vector<pll> gr[N];
void dijkstra(ll src,ll dist[])
{
    priority_queue<pll,vector<pll>,greater<pll> > qq;
    for(int i=1;i<=n;i++) dist[i]=inf;
    dist[src]=0;
    qq.emplace(0,src);
    while(qq.size())
    {
        auto [d,u]=qq.top();
        qq.pop();
        if(dist[u]!=d) continue;
        for(auto [v,c]:gr[u])
        {
            if(minimize(dist[v],d+c))
            {
                qq.emplace(dist[v],v);
            }
        }
    }
}
struct info
{
    ll d,u,s;
    info(ll _d=0,ll _u=0,ll _s=0)
    {
        d=_d;
        u=_u;
        s=_s;
    }
    bool operator <(const info &o) const
    {
        return d>o.d;
    }
};
ll dijkstra2(ll st,ll en)
{
    memset(f,0x3f,sizeof f);
    priority_queue<info> qq;
    qq.emplace(0,st,0);
    f[st][0]=0;
    while(qq.size())
    {
        auto [d,u,s]=qq.top();
        qq.pop();
        if(d!=f[u][s]) continue;
        for(auto [v,c]:gr[u])
        {
            if(c==0)
            {
                if(s==2) continue;
                if(minimize(f[v][s|1],f[u][s]))
                {
                    qq.emplace(f[v][s|1],v,s|1);
                }
            }
            else
            {
                if(s==1)
                {
                    if(minimize(f[v][2],f[u][s]+c))
                    {
                        qq.emplace(f[v][2],v,2);
                    }
                }
                else
                {
                    if(minimize(f[v][s],f[u][s]+c))
                    {
                        qq.emplace(f[v][s],v,s);
                    }
                }
            }
        }
    }
    return min(min(f[en][0],f[en][1]),f[en][2]);
}
int main()
{
    online();
    ll s,t,u,v;
    cin>>n>>m;
    cin>>s>>t;
    cin>>u>>v;
    for(int i=1;i<=m;i++)
    {
        ll u,v,c;
        cin>>u>>v>>c;
        U[i]=u;
        V[i]=v;
        C[i]=c;
        gr[u].emplace_back(v,c);
        gr[v].emplace_back(u,c);
    }
    dijkstra(s,dists);
    dijkstra(t,distt);
    for(int i=1;i<=m;i++)
    {
        if(dists[U[i]]+C[i]+distt[V[i]]==dists[t])
        {
            gr[U[i]].emplace_back(V[i],0);
        }
        if(dists[V[i]]+C[i]+distt[U[i]]==dists[t])
        {
            gr[V[i]].emplace_back(U[i],0);
        }
    }
    cout<<min(dijkstra2(u,v),dijkstra2(v,u));
}

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