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QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#419157#8720. BFS 序 0tzxydby#WA 2138ms92544kbC++202.0kb2024-05-23 18:18:392024-05-23 18:18:40

Judging History

你现在查看的是最新测评结果

  • [2024-05-23 18:18:40]
  • 评测
  • 测评结果:WA
  • 用时:2138ms
  • 内存:92544kb
  • [2024-05-23 18:18:39]
  • 提交

answer

#include<bits/stdc++.h>
using namespace std;
const int N=300005;
int n,m,q,fa[N][20],dep[N],a[N],d[N],dfn[N],low[N],tim,in[N],st[N],tp,ok;
vector<int>e[N],g[N],p;
void dfs(int u,int f)
{
	fa[u][0]=f;
	dep[u]=dep[f]+1;
	for(auto v:e[u])
		if(v!=f)
			dfs(v,u);
}
int lca(int u,int v)
{
	if(dep[u]<dep[v])
		swap(u,v);
	for(int i=18;i>=0;i--)
		if(dep[fa[u][i]]>=dep[v])
			u=fa[u][i];
	if(u==v)
		return u;
	for(int i=18;i>=0;i--)
		if(fa[u][i]!=fa[v][i])
			u=fa[u][i],v=fa[v][i];
	return fa[u][0];
}
int cal(int u,int v)
{
	for(int i=18;i>=0;i--)
		if(dep[fa[u][i]]>dep[v])
			u=fa[u][i];
	return u;
}
void tarjan(int u)
{
	dfn[u]=low[u]=++tim;
	st[++tp]=u,in[u]=1;
	for(auto v:g[u])
	{
		if(!dfn[v])
		{
			tarjan(v);
			low[u]=min(low[u],low[v]);
		}
		else if(in[v])
			low[u]=min(low[u],dfn[v]);
	}
	if(dfn[u]==low[u])
	{
		int v;
		do
		{
			v=st[tp--];
			in[v]=0;
			if(v!=u)
				ok=0;
		}while(v!=u);
	}
}
int main()
{
	scanf("%d",&n);
	for(int i=2;i<=n;i++)
	{
		int x;
		scanf("%d",&x);
		e[x].push_back(i);
	}
	dfs(1,0);
	for(int j=1;j<=18;j++)
		for(int i=1;i<=n;i++)
			fa[i][j]=fa[fa[i][j-1]][j-1];
	scanf("%d",&q);
	while(q--)
	{
		scanf("%d",&m);
		for(int i=1;i<=m;i++)
			scanf("%d",&a[i]);
		for(int i=1;i<=m;i++)
			d[i]=dep[a[i]];
		ok=1;
		for(int i=1;i<m;i++)
			if(d[i]>d[i+1])
				ok=0;
		if(!ok)
		{
			puts("No");
			continue;
		}
		for(int i=1;i<=m;i++)
		{
			int j=i;
			while(j<m&&d[j+1]==d[i])
				j++;
			for(int k=i;k<j;k++)
			{
				int l=lca(a[i],a[i+1]);
				int u=cal(a[i],l),v=cal(a[i],l);
				p.push_back(u);
				p.push_back(v);
				g[u].push_back(v);
			}
			sort(p.begin(),p.end());
			p.erase(unique(p.begin(),p.end()),p.end());
			for(auto u:p)
				if(!dfn[u])
					tarjan(u);
			if(!ok)
				break;
			for(auto u:p)
			{
				g[u].clear();
				dfn[u]=low[u]=in[u]=0;
			}
			tim=tp=0;
			p.clear();
		}
		puts(ok?"Yes":"No");
	}
	return 0;
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 0ms
memory: 11960kb

input:

6
1 1 3 2 4
10
4 3 6 2 5
1 4
3 2 4 5
5 2 5 4 6 3
3 1 4 2
3 5 6 3
5 4 5 2 6 1
4 4 3 2 5
4 4 6 2 3
3 3 2 6

output:

No
Yes
Yes
No
No
No
No
No
No
Yes

result:

ok 10 token(s): yes count is 3, no count is 7

Test #2:

score: -100
Wrong Answer
time: 2138ms
memory: 92544kb

input:

300000
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1...

output:

Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
...

result:

wrong answer expected NO, found YES [1st token]