- Time limit: 1.00 s
- Memory limit: 512 MB
You are given a string that consists of n characters between a–z. The positions of the string are indexed 1,2,\dots,n.
Your task is to process m operations of the following types:
- Change the character at position k to x
- Check if the substring from position a to position b is a palindrome
The first input line has two integers n and m: the length of the string and the number of operations.
The next line has a string that consists of n characters.
Finally, there are m lines that describe the operations. Each line is of the form "1 k x" or "2 a b".
For each operation 2, print YES if the substring is a palindrome and NO otherwise.
- 1 \le n, m \le 2 \cdot 10^5
- 1 \le k \le n
- 1 \le a \le b \le n
7 5 aybabtu 2 3 5 1 3 x 2 3 5 1 5 x 2 3 5
YES NO YES