题目描述
Yuezheng Ling gives Luo Tianyi a tree which has $n$ nodes, rooted at $1$.
Luo Tianyi will tell you that the parent of the $i$-th node is $a_i$ ($1 \leq a_i<i$ for $2 \le i \le n$), and she will ask you to perform $q$ queries of $2$ types:
- She'll give you three integers $l$, $r$ and $x$ ($2 \le l \le r \le n$, $1 \le x \le 10^5$). You need to replace $a_i$ with $\max(a_i-x,1)$ for all $i$ with $l \leq i \leq r$.
- She'll give you two integers $u$, $v$ ($1 \le u, v \le n$). You need to find the LCA of nodes $u$ and $v$ (their lowest common ancestor).
Input
The first line contains two integers $n$ and $q$ ($2\leq n,q \leq 10^5$) — the number of nodes and the number of queries, respectively.
The second line contains $n-1$ integers $a_2, a_3,\dots, a_n$ ($1 \le a_i < i$), where $a_i$ is the parent of the node $i$.
Next $q$ lines contain queries. For each query, the first integer of each line is $t$ ($t = 1$ or $2$) — the type of the query.
If $t = 1$, this represents the query of the first type. Then, three integers will follow: $l$, $r$, $x$ ($2 \le l \le r \le n$, $1 \le x \le 10^5$), meaning that you have to replace $a_i$ with $\max(a_i-x,1)$ for all $i$ with $l \leq i \leq r$.
If $t = 2$, this represents the query of the second type. Then, two integers will follow: $u$ and $v$ ($1 \le u, v \le n$), and you have to find the LCA of $u$ and $v$.
It's guaranteed that there is at least one query of the second type.
Output
For each query of the second type output answer on a new line.
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分
样例输入
样例输出
提示
The tree in example is shown below.
After the query of the first type, the tree changes and is looking as shown below.