Codeforces Round 722 (Div. 1)
C
Trees of Tranquillity
Codeforces
2300
原题
← BD →
翻译中…

Soroush and Keshi each have a labeled and rooted tree on $n$ vertices. Both of their trees are rooted from vertex $1$.

翻译中…

Soroush and Keshi used to be at war. After endless decades of fighting, they finally became allies to prepare a Codeforces round. To celebrate this fortunate event, they decided to make a memorial graph on $n$ vertices.

翻译中…

They add an edge between vertices $u$ and $v$ in the memorial graph if both of the following conditions hold:

翻译中…
  • One of $u$ or $v$ is the ancestor of the other in Soroush's tree.
  • Neither of $u$ or $v$ is the ancestor of the other in Keshi's tree.
翻译中…

Here vertex $u$ is considered ancestor of vertex $v$, if $u$ lies on the path from $1$ (the root) to the $v$.

翻译中…

Popping out of nowhere, Mashtali tried to find the maximum clique in the memorial graph for no reason. He failed because the graph was too big.

翻译中…

Help Mashtali by finding the size of the maximum clique in the memorial graph.

翻译中…

As a reminder, clique is a subset of vertices of the graph, each two of which are connected by an edge.

翻译中…

Input

翻译中…

The first line contains an integer $t$ $(1\le t\le 3 \cdot 10^5)$ — the number of test cases. The description of the test cases follows.

翻译中…

The first line of each test case contains an integer $n$ $(2\le n\le 3 \cdot 10^5)$.

翻译中…

The second line of each test case contains $n-1$ integers $a_2, \ldots, a_n$ $(1 \le a_i \lt i)$, $a_i$ being the parent of the vertex $i$ in Soroush's tree.

翻译中…

The third line of each test case contains $n-1$ integers $b_2, \ldots, b_n$ $(1 \le b_i \lt i)$, $b_i$ being the parent of the vertex $i$ in Keshi's tree.

翻译中…

It is guaranteed that the given graphs are trees.

翻译中…

It is guaranteed that the sum of $n$ over all test cases doesn't exceed $3 \cdot 10^5$.

翻译中…

Output

翻译中…

For each test case print a single integer — the size of the maximum clique in the memorial graph.

翻译中…

Note

翻译中…

In the first and third test cases, you can pick any vertex.

翻译中…

In the second test case, one of the maximum cliques is $\{2, 3, 4, 5\}$.

翻译中…

In the fourth test case, one of the maximum cliques is $\{3, 4, 6\}$.

翻译中…

样例

Input #1
4
4
1 2 3
1 2 3
5
1 2 3 4
1 1 1 1
6
1 1 1 1 2
1 2 1 2 2
7
1 1 3 4 4 5
1 2 1 4 2 5
Output #1
1
4
1
3
InputCopy OutputCopy
题目信息
题号
1528C
时间限制
3 s
内存限制
256 MB
标签
数据结构
DFS 及类似
贪心
树

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。