A15662 | $Notepad#$

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内存限制256MB

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题目描述

You want to type the string $s$ , consisting of $n$ lowercase Latin letters, using your favorite text editor Notepad#. Notepad# supports two kinds of operations: - append any letter to the end of the string; - copy a continuous substring of an already typed string and paste this substring to the end of the string. Can you type string $s$ in strictly less than $n$ operations?

The first line contains a single integer $t$ ( $1 \le t \le 10^4$ ) — the number of testcases. The first line of each testcase contains a single integer $n$ ( $1 \le n \le 2 \cdot 10^5$ ) — the length of the string $s$ . The second line contains a string $s$ , consisting of $n$ lowercase Latin letters. The sum of $n$ doesn't exceed $2 \cdot 10^5$ over all testcases.

For each testcase, print "YES" if you can type string $s$ in strictly less than $n$ operations. Otherwise, print "NO".

输入 #1

6
10
codeforces
8
labacaba
5
uohhh
16
isthissuffixtree
1
x
4
momo

输出 #1

NO
YES
NO
YES
NO
YES

C++ 编辑器

输入

输出