124 – ZOJ Monthly, March 2013 – A, A Simple Tree Problem, 修改子树 和查询。

Given a rooted tree, each node has a boolean (0 or 1) labeled on it. Initially, all the labels are 0.

We define this kind of operation: given a subtree, negate all its labels.

And we want to query the numbers of 1’s of a subtree.


Multiple test cases.

First line, two integer N and M, denoting the numbers of nodes and numbers of operations and queries.(1<=N<=100000, 1<=M<=10000)

Then a line with N-1 integers, denoting the parent of node 2..N. Root is node 1.

Then M lines, each line are in the format “o node” or “q node“, denoting we want to operate or query on the subtree with root of a certain node.


For each query, output an integer in a line.

Output a blank line after each test case.

Sample Input

3 2
1 1
o 2
q 1

Sample Output


Problem’s Author: CUI, Tianyi

批量地 修改子树 可以被看做段修改(把树通过一个入点出点路径序列来表示),这样即转化为了线段树的段修改和段查询。


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