201450: [AtCoder]ARC145 A - AB Palindrome
Memory Limit：1024 MB
Time Limit：2 S
Judge Style：Text Compare
Creator：
Submit：0
Solved：0
Description
Score : $400$ points
Problem Statement
You are given a string $S$ of length $N$ consisting of A and B.
You can repeat the following operation zero or more times:
- choose a pair of adjacent characters in $S$ and replace them with
AB.
Determine whether $S$ can be turned into a palindrome.
What is a palindrome?
A string $T$ is a palindrome if and only if, for every integer $i$ ($1 \le i \le |T|$), the $i$-th character from the beginning and the $i$-th character from the end are the same, where $|T|$ is the length of $T$.Constraints
- $2 \leq N \leq 2\times 10^5$
- $S$ is a string of length $N$ consisting of
AandB.
Input
Input is given from Standard Input in the following format:
$N$ $S$
Output
If $S$ can be turned into a palindrome, print Yes; otherwise, print No.
Sample Input 1
3 BBA
Sample Output 1
Yes
Replacing the $2$-nd and $3$-rd characters, BA, with AB will turn $S$ into BAB, a palindrome.
Sample Input 2
4 ABAB
Sample Output 2
No
No sequence of operations can turn $S$ into a palindrome.