1140 : Parenthesis
Time Limit: 1 Sec Memory Limit: 128 MB Submitted: 121 Solved: 24Description
Bobo has a balanced parenthesis sequence P=p1 p2…pn of length n and q questions.
The i-th question is whether P remains balanced after pai and pbi swapped. Note that questions are individual so that they have no affect on others.
Parenthesis sequence S is balanced if and only if:
- S is empty;
- or there exists balanced parenthesis sequence A,B such that S=AB;
- or there exists balanced parenthesis sequence S’ such that S=(S’).
Input
The input contains at most 30 sets. For each set:
The first line contains two integers n,q (2 ≤ n ≤ 105, 1 ≤ q ≤ 105).
The second line contains n characters p1 p2…pn.
The i-th of the last q lines contains 2 integers ai,bi (1 ≤ ai, bi ≤ n, ai ≠ bi).
Output
For each question, output “Yes” if P remains balanced, or “No” otherwise.
Sample
4 2 (()) 1 3 2 3 2 1 () 1 2
No Yes No
Hint
Author
ftiasch