CF1730D.Prefixes and Suffixes

You have two strings $s_1$ and $s_2$ of length $n$, consisting of lowercase English letters. You can perform the following operation any (possibly zero) number of times:

• Choose a positive integer $1 \leq k \leq n$.
• Swap the prefix of the string $s_1$ and the suffix of the string $s_2$ of length $k$.

Is it possible to make these two strings equal by doing described operations?

你有两个长度为 $n$ 的字符串 $s_1$ 和 $s_2$，均由小写英文字母组成。你可以执行以下操作任意次（可以为零次）：

• 选择一个正整数 $1 \leq k \leq n$；
• 交换字符串 $s_1$ 的长度为 $k$ 的前缀与字符串 $s_2$ 的长度为 $k$ 的后缀。

能否通过执行上述操作使得这两个字符串相等？

The first line contains a single integer $t$ ($1 \le t \le 10^4$) — the number of test cases. Then the test cases follow.

Each test case consists of three lines.

The first line contains a single integer $n$ ($1 \le n \le 10^5$) — the length of the strings $s_1$ and $s_2$.

The second line contains the string $s_1$ of length $n$, consisting of lowercase English letters.

The third line contains the string $s_2$ of length $n$, consisting of lowercase English letters.

It is guaranteed that the sum of $n$ for all test cases does not exceed $2 \cdot 10^5$.

第一行包含一个整数 $t$（$1 \le t \le 10^4$）—— 表示测试用例的数量。随后是各测试用例。

每个测试用例由三行组成。

第一行包含一个整数 $n$（$1 \le n \le 10^5$）—— 表示字符串 $s_1$ 和 $s_2$ 的长度。

第二行包含一个长度为 $n$ 的字符串 $s_1$，由小写英文字母组成。

第三行包含一个长度为 $n$ 的字符串 $s_2$，由小写英文字母组成。

保证所有测试用例的 $n$ 之和不超过 $2 \cdot 10^5$。

For each test case, print "YES" if it is possible to make the strings equal, and "NO" otherwise.

对于每个测试用例，如果可以使两个字符串相等，则输出 “YES”；否则输出 “NO”。

In the first test case:

• Initially $s_1 = \mathtt{cbc}$, $s_2 = \mathtt{aba}$.
• Operation with $k = 1$, after the operation $s_1 = \mathtt{abc}$, $s_2 = \mathtt{abc}$.

In the second test case:

• Initially $s_1 = \mathtt{abcaa}$, $s_2 = \mathtt{cbabb}$.
• Operation with $k = 2$, after the operation $s_1 = \mathtt{bbcaa}$, $s_2 = \mathtt{cbaab}$.
• Operation with $k = 3$, after the operation $s_1 = \mathtt{aabaa}$, $s_2 = \mathtt{cbbbc}$.
• Operation with $k = 1$, after the operation $s_1 = \mathtt{cabaa}$, $s_2 = \mathtt{cbbba}$.
• Operation with $k = 2$, after the operation $s_1 = \mathtt{babaa}$, $s_2 = \mathtt{cbbca}$.
• Operation with $k = 1$, after the operation $s_1 = \mathtt{aabaa}$, $s_2 = \mathtt{cbbcb}$.
• Operation with $k = 2$, after the operation $s_1 = \mathtt{cbbaa}$, $s_2 = \mathtt{cbbaa}$.

In the third test case, it's impossible to make strings equal.

在第一个测试用例中：

• 初始时 $s_1 = \mathtt{cbc}$，$s_2 = \mathtt{aba}$。
• 执行 $k = 1$ 的操作后，$s_1 = \mathtt{abc}$，$s_2 = \mathtt{abc}$。

在第二个测试用例中：

• 初始时 $s_1 = \mathtt{abcaa}$，$s_2 = \mathtt{cbabb}$。
• 执行 $k = 2$ 的操作后，$s_1 = \mathtt{bbcaa}$，$s_2 = \mathtt{cbaab}$。
• 执行 $k = 3$ 的操作后，$s_1 = \mathtt{aabaa}$，$s_2 = \mathtt{cbbbc}$。
• 执行 $k = 1$ 的操作后，$s_1 = \mathtt{cabaa}$，$s_2 = \mathtt{cbbba}$。
• 执行 $k = 2$ 的操作后，$s_1 = \mathtt{babaa}$，$s_2 = \mathtt{cbbca}$。
• 执行 $k = 1$ 的操作后，$s_1 = \mathtt{aabaa}$，$s_2 = \mathtt{cbbcb}$。
• 执行 $k = 2$ 的操作后，$s_1 = \mathtt{cbbaa}$，$s_2 = \mathtt{cbbaa}$。

在第三个测试用例中，无法使两个字符串相等。