Score : $300$ points

问题描述

你将获得两个正整数 $N$ 和 $Q$，以及一个长度为 $N$ 的由小写英文字母组成的字符串 $S$。

处理 $Q$ 个查询。每个查询属于以下两种类型之一。

• 1 x: 依次执行 $x$ 次以下操作：删除 $S$ 的最后一个字符，并将其添加到开头。
• 2 x: 输出 $S$ 的第 $x$ 个字符。

以上为通义千问 qwen-max 翻译，仅供参考。

Problem Statement

You are given positive integers $N$ and $Q$, and a string $S$ of length $N$ consisting of lowercase English letters.

Process $Q$ queries. Each query is of one of the following two types.

• 1 x: Perform the following $x$ times in a row: delete the last character of $S$ and append it to the beginning.
• 2 x: Print the $x$-th character of $S$.

Constraints

• $2 \le N \le 5 \times 10^5$
• $1 \le Q \le 5 \times 10^5$
• $1 \le x \le N$
• $|S|=N$
• $S$ consists of lowercase English letters.
• At least one query in the format 2 x.
• $N$, $Q$, $x$ are all integers.

Input

Input is given from Standard Input in the following format:

$N$ $Q$

$S$

$\mathrm{query}_1$

$\mathrm{query}_2$

$\vdots$

$\mathrm{query}_Q$

Each query is in the following format, where $t$ is $1$ or $2$:

$t$ $x$

Output

For each query in the format 2 x, print the answer in a single line.

Sample Input 1

3 3
abc
2 2
1 1
2 2

Sample Output 1

b
a

In the $1$-st query, $S$ is abc, so the $2$-nd character b should be printed. In the $2$-nd query, $S$ is changed from abc to cab. In the $3$-rd query, $S$ is cab, so the $2$-nd character a should be printed.

Sample Input 2

10 8
dsuccxulnl
2 4
2 7
1 2
2 7
1 1
1 2
1 3
2 5

Sample Output 2

c
u
c
u

update @ 2024/3/10 10:57:21