Codeforces Round 526 (Div. 2)
F
Max Mex
Codeforces
未评级
原题
← E→
翻译中…

Once Grisha found a tree (connected graph without cycles) with a root in node $1$.

翻译中…

But this tree was not just a tree. A permutation $p$ of integers from $0$ to $n - 1$ is written in nodes, a number $p_i$ is written in node $i$.

翻译中…

As Grisha likes to invent some strange and interesting problems for himself, but not always can solve them, you need to help him deal with two types of queries on this tree.

翻译中…

Let's define a function $MEX(S)$, where $S$ is a set of non-negative integers, as a smallest non-negative integer that is not included in this set.

翻译中…

Let $l$ be a simple path in this tree. So let's define indices of nodes which lie on $l$ as $u_1$, $u_2$, $\ldots$, $u_k$.

翻译中…

Define $V(l)$ as a set {$p_{u_1}$, $p_{u_2}$, $\ldots$ , $p_{u_k}$}.

翻译中…

Then queries are:

翻译中…
  1. For two nodes $i$ and $j$, swap $p_i$ and $p_j$.
  2. Find the maximum value of $MEX(V(l))$ in all possible $l$.
翻译中…

Input

翻译中…

The first line contains a single integer $n$ ($2 \leq n \leq 2 \cdot 10^5$) — the number of nodes of a tree.

翻译中…

The second line contains $n$ integers — $p_1$, $p_2$, $\ldots$, $p_n$ ($0\leq p_i \lt n$) — the permutation $p$, it's guaranteed that all numbers are different .

翻译中…

The third line contains $n - 1$ integers — $d_2$, $d_3$, $\ldots$, $d_n$ ($1 \leq d_i \lt i$), where $d_i$ is a direct ancestor of node $i$ in a tree.

翻译中…

The fourth line contains a single integer $q$ ($1 \leq q \leq 2 \cdot 10^5$) — the number of queries.

翻译中…

The following $q$ lines contain the description of queries:

翻译中…

At the beginning of each of next $q$ lines, there is a single integer $t$ ($1$ or $2$) — the type of a query:

翻译中…
  1. If $t = 1$, the line also contains two integers $i$ and $j$ ($1 \leq i, j \leq n$) — the indices of nodes, where values of the permutation should be swapped.
  2. If $t = 2$, you need to find the maximum value of $MEX(V(l))$ in all possible $l$.
翻译中…

Output

翻译中…

For each type 2 query print a single integer — the answer for this query.

翻译中…

Note

翻译中…

Number written in brackets is a permutation value of a node.

翻译中…

image

翻译中…

In the first example, for the first query, optimal path is a path from node $1$ to node $5$. For it, set of values is $\{0, 1, 2\}$ and $MEX$ is $3$.

翻译中…

image

翻译中…

For the third query, optimal path is a path from node $5$ to node $6$. For it, set of values is $\{0, 1, 4\}$ and $MEX$ is $2$.

翻译中…

image

翻译中…

In the second example, for the first query, optimal path is a path from node $2$ to node $6$. For it, set of values is $\{0, 1, 2, 5\}$ and $MEX$ is $3$.

翻译中…

image

翻译中…

For the third query, optimal path is a path from node $5$ to node $6$. For it, set of values is $\{0, 1, 3\}$ and $MEX$ is $2$.

翻译中…

image

翻译中…

For the fifth query, optimal path is a path from node $5$ to node $2$. For it, set of values is $\{0, 1, 2, 3\}$ and $MEX$ is $4$.

翻译中…

image

翻译中…

For the seventh query, optimal path is a path from node $5$ to node $4$. For it, set of values is $\{0, 1, 2, 3\}$ and $MEX$ is $4$.

翻译中…

image

翻译中…

For the ninth query, optimal path is a path from node $6$ to node $5$. For it, set of values is $\{0, 1, 3\}$ and $MEX$ is $2$.

翻译中…

样例

Input #1
6
2 5 0 3 1 4
1 1 3 3 3
3
2
1 6 3
2
Output #1
3
2
InputCopy OutputCopy
Input #2
6
5 2 1 4 3 0
1 1 1 3 3
9
2
1 5 3
2
1 6 1
2
1 4 2
2
1 1 6
2
Output #2
3
2
4
4
2
InputCopy OutputCopy
题目信息
题号
1084F
时间限制
3 s
内存限制
256 MB

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。