Submission #866105

#	Time	Username	Problem	Language	Result	Execution time	Memory
866105		20163070	Commuter Pass (JOI18_commuter_pass)	C++14	100 / 100	375 ms	30052 KiB

commuter_pass

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

#define int long long

const int inf=1e15,N=2e5+10;

struct heap
{
	int node;
	int len;
	bool operator < (const heap&x)const
	{
		return x.len<len;
	}
};

priority_queue<heap> q;

struct Edge
{
	int to,next,len;
}edge[N<<1];

int num,head[N],vis[N],n,m,s,t,u,v;
int du[N],dv[N],ds[N],dt[N],f[N],g[N],ans;

void add(int x,int y,int z)
{
	edge[++num]=(Edge){y,head[x],z},head[x]=num;
}

void dijk(int st,int *dis)
{
	for(int i=1;i<=n;i++)
	{
		vis[i]=0;
		dis[i]=inf;
	}
	dis[st]=0;
	q.push((heap){st,0});
	while(q.size())
	{
		int u=q.top().node;
		q.pop();
		if(vis[u]) continue;
		vis[u]=1;
		for(int i=head[u];i;i=edge[i].next)
		{
			int v=edge[i].to;
			if(dis[v]>dis[u]+edge[i].len)
			{
				dis[v]=dis[u]+edge[i].len;
				if(!vis[v]) q.push((heap){v,dis[v]});
			}
		}
	}
}

void dfs(int u)
{
	if(vis[u]) return;
	vis[u]=1;
	f[u]=dv[u],g[u]=du[u];
	for(int i=head[u];i;i=edge[i].next)
	{
		int v=edge[i].to;
		if(ds[u]+dt[v]+edge[i].len>ds[t]) continue;
		dfs(v);
		f[u]=min(f[u],f[v]);
		g[u]=min(g[u],g[v]);
	}
	ans=min(ans,min(f[u]+du[u],g[u]+dv[u]));
}

signed main()
{
	cin>>n>>m;
	cin>>s>>t>>u>>v;
	for(int i=1;i<=m;i++)
	{
		int x,y,z;
		cin>>x>>y>>z;
		add(x,y,z),add(y,x,z);
	}
	dijk(s,ds);
	dijk(t,dt);
	dijk(u,du);
	dijk(v,dv);
	ans=du[v];
	for(int i=1;i<=n;i++) vis[i]=0;
	dfs(s);
	cout<<ans;
	return 0;
}

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