codeforces#P1017G. The Tree
The Tree
Description
Abendsen assigned a mission to Juliana. In this mission, Juliana has a rooted tree with $n$ vertices. Vertex number $1$ is the root of this tree. Each vertex can be either black or white. At first, all vertices are white. Juliana is asked to process $q$ queries. Each query is one of three types:
- If vertex $v$ is white, mark it as black; otherwise, perform this operation on all direct sons of $v$ instead.
- Mark all vertices in the subtree of $v$ (including $v$) as white.
- Find the color of the $i$-th vertex.
Can you help Juliana to process all these queries?
The first line contains two integers $n$ and $q$ ($2\leq n\leq 10^5$, $1\leq q\leq 10^5$) — the number of vertices and the number of queries.
The second line contains $n-1$ integers $p_2, p_3, \ldots, p_n$ ($1\leq p_i<i$), where $p_i$ means that there is an edge between vertices $i$ and $p_i$.
Each of the next $q$ lines contains two integers $t_i$ and $v_i$ ($1\leq t_i\leq 3$, $1\leq v_i\leq n$) — the type of the $i$-th query and the vertex of the $i$-th query.
It is guaranteed that the given graph is a tree.
For each query of type $3$, print "black" if the vertex is black; otherwise, print "white".
Input
The first line contains two integers $n$ and $q$ ($2\leq n\leq 10^5$, $1\leq q\leq 10^5$) — the number of vertices and the number of queries.
The second line contains $n-1$ integers $p_2, p_3, \ldots, p_n$ ($1\leq p_i<i$), where $p_i$ means that there is an edge between vertices $i$ and $p_i$.
Each of the next $q$ lines contains two integers $t_i$ and $v_i$ ($1\leq t_i\leq 3$, $1\leq v_i\leq n$) — the type of the $i$-th query and the vertex of the $i$-th query.
It is guaranteed that the given graph is a tree.
Output
For each query of type $3$, print "black" if the vertex is black; otherwise, print "white".
Samples
8 10
1 2 1 2 5 4 5
1 2
3 2
3 1
1 1
1 1
3 5
3 7
3 4
2 2
3 5
black
white
black
white
black
white
8 11
1 1 2 3 3 6 6
1 1
1 1
1 3
3 2
3 4
3 6
3 7
2 3
1 6
3 7
3 6
black
white
black
white
white
black
Note
The first example is shown on the picture below.
The second example is shown on the picture below.