- Time limit: 1.00 s
- Memory limit: 512 MB
A company has n employees, who form a tree hierarchy where each employee has a boss, except for the general director.
Your task is to process q queries of the form: who is the lowest common boss of employees a and b in the hierarchy?
The first input line has two integers n and q: the number of employees and queries. The employees are numbered 1,2,\dots,n, and employee 1 is the general director.
The next line has n-1 integers e_2,e_3,\dots,e_n: for each employee 2,3,\dots,n their boss.
Finally, there are q lines describing the queries. Each line has two integers a and b: who is the lowest common boss of employees a and b?
Print the answer for each query.
- 1 \le n,q \le 2 \cdot 10^5
- 1 \le e_i \le i-1
- 1 \le a,b \le n
5 3 1 1 3 3 4 5 2 5 1 4
3 1 1