0582. Kill Process

https://leetcode.com/problems/kill-process

Description

You have n processes forming a rooted tree structure. You are given two integer arrays pid and ppid, where pid[i] is the ID of the ith process and ppid[i] is the ID of the ith process's parent process.

Each process has only one parent process but may have multiple children processes. Only one process has ppid[i] = 0, which means this process has no parent process (the root of the tree).

When a process is killed, all of its children processes will also be killed.

Given an integer kill representing the ID of a process you want to kill, return a list of the IDs of the processes that will be killed. You may return the answer in any order.

Example 1:

**Input:** pid = [1,3,10,5], ppid = [3,0,5,3], kill = 5
**Output:** [5,10]
**Explanation:** The processes colored in red are the processes that should be killed.

Example 2:

**Input:** pid = [1], ppid = [0], kill = 1
**Output:** [1]

Constraints:

• n == pid.length

• n == ppid.length

• 1 <= n <= 5 * 104

• 1 <= pid[i] <= 5 * 104

• 0 <= ppid[i] <= 5 * 104

• Only one process has no parent.

• All the values of pid are unique.

• kill is guaranteed to be in pid.

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