A12796. Red Blue Tree
编程题
普及/提高-
知识点
题目描述
You are given a tree of $n$ nodes. The tree is rooted at node $1$ , which is not considered as a leaf regardless of its degree.
Each leaf of the tree has one of the two colors: red or blue. Leaf node $v$ initially has color $s_{v}$ .
The color of each of the internal nodes (including the root) is determined as follows.
- Let $b$ be the number of blue immediate children, and $r$ be the number of red immediate children of a given vertex.
- Then the color of this vertex is blue if and only if $b - r \ge k$ , otherwise red.
Integer $k$ is a parameter that is same for all the nodes.
You need to handle the following types of queries:
- 1 v: print the color of node $v$ ;
- 2 v c: change the color of leaf $v$ to $c$ ( $c = 0$ means red, $c = 1$ means blue);
- 3 h: update the current value of $k$ to $h$ .
Each leaf of the tree has one of the two colors: red or blue. Leaf node $v$ initially has color $s_{v}$ .
The color of each of the internal nodes (including the root) is determined as follows.
- Let $b$ be the number of blue immediate children, and $r$ be the number of red immediate children of a given vertex.
- Then the color of this vertex is blue if and only if $b - r \ge k$ , otherwise red.
Integer $k$ is a parameter that is same for all the nodes.
You need to handle the following types of queries:
- 1 v: print the color of node $v$ ;
- 2 v c: change the color of leaf $v$ to $c$ ( $c = 0$ means red, $c = 1$ means blue);
- 3 h: update the current value of $k$ to $h$ .
输入格式
The first line of the input consists of two integers $n$ and $k$ ( $2 \le n \le 10^{5}$ , $-n \le k \le n$ ) — the number of nodes and the initial parameter $k$ .
Each of the next $n - 1$ lines contains two integers $u$ and $v$ ( $1 \le u,v \le n$ ), denoting that there is an edge between vertices $u$ and $v$ .
The next line consists of $n$ space separated integers — the initial array $s$ ( $-1 \le s_i \le 1$ ). $s_{i} = 0$ means that the color of node $i$ is red. $s_{i} = 1$ means that the color of node $i$ is blue. $s_{i} = -1$ means that the node $i$ is not a leaf.
The next line contains an integer $q$ ( $1 \le q \le 10^5$ ), the number of queries.
$q$ lines follow, each containing a query in one of the following queries:
- 1 v ( $1 \le v \le n$ ): print the color of node $v$ ;
- 2 v c ( $1 \le v \le n$ , $c = 0$ or $c = 1$ ): change the color of leaf $v$ to $c$ ( $c = 0$ means red, $c = 1$ means blue). It is guaranteed that $v$ is a leaf;
- 3 h ( $-n \le h \le n$ ): update the current value of $k$ to $h$ .
Each of the next $n - 1$ lines contains two integers $u$ and $v$ ( $1 \le u,v \le n$ ), denoting that there is an edge between vertices $u$ and $v$ .
The next line consists of $n$ space separated integers — the initial array $s$ ( $-1 \le s_i \le 1$ ). $s_{i} = 0$ means that the color of node $i$ is red. $s_{i} = 1$ means that the color of node $i$ is blue. $s_{i} = -1$ means that the node $i$ is not a leaf.
The next line contains an integer $q$ ( $1 \le q \le 10^5$ ), the number of queries.
$q$ lines follow, each containing a query in one of the following queries:
- 1 v ( $1 \le v \le n$ ): print the color of node $v$ ;
- 2 v c ( $1 \le v \le n$ , $c = 0$ or $c = 1$ ): change the color of leaf $v$ to $c$ ( $c = 0$ means red, $c = 1$ means blue). It is guaranteed that $v$ is a leaf;
- 3 h ( $-n \le h \le n$ ): update the current value of $k$ to $h$ .
输出格式
For each query of the first type, print $0$ if the color of vertex $v$ is red, and $1$ otherwise.
输入输出样例
输入 #1
5 2 1 2 1 3 2 4 2 5 -1 -1 0 1 0 9 1 1 1 2 3 -2 1 1 1 2 3 1 2 5 1 1 1 1 2
输出 #1
0 0 1 1 0 1
说明/提示
Figures:(i) The initial tree
(ii) The tree after the 3rd query
(iii) The tree after the 7th query

(ii) The tree after the 3rd query
(iii) The tree after the 7th query
