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QOJ
| ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
|---|---|---|---|---|---|---|---|---|---|
| #419222 | #8720. BFS 序 0 | tzxydby | WA | 186ms | 61252kb | C++20 | 2.1kb | 2024-05-23 19:04:35 | 2024-05-23 19:07:57 |
Judging History
answer
#include<bits/stdc++.h>
using namespace std;
const int N=500005;
int n,m,q,fa[N][20],dep[N],a[N],d[N],dfn[N],low[N],tim,in[N],st[N],tp,ok,vis[N];
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]);
ok=1;
for(int i=1;i<=m;i++)
{
if(vis[a[i]])
ok=0;
vis[a[i]]=1;
}
for(int i=1;i<=m;i++)
vis[a[i]]=0;
for(int i=1;i<=m;i++)
d[i]=dep[a[i]];
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[k],a[k+1]);
int u=cal(a[k],l),v=cal(a[k+1],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);
for(auto u:p)
{
g[u].clear();
dfn[u]=low[u]=in[u]=0;
}
tim=tp=0;
p.clear();
i=j;
if(!ok)
break;
}
puts(ok?"Yes":"No");
}
return 0;
}
Details
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Test #1:
score: 100
Accepted
time: 0ms
memory: 16016kb
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: 186ms
memory: 61252kb
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:
No Yes Yes Yes No No No No No No Yes Yes No Yes No Yes Yes Yes No No No No Yes No No Yes No No No No Yes Yes Yes No No Yes No No No No No No No Yes No Yes No Yes No No No No Yes Yes Yes No No Yes No No No No No Yes Yes No No No No No Yes Yes No Yes No No No Yes No No Yes No No Yes Yes Yes No No No Y...
result:
wrong answer expected NO, found YES [181st token]