Peculiar Movie Preferences

2000ms

524288K

Description:

Mihai plans to watch a movie. He only likes palindromic movies, so he wants to skip some (possibly zero) scenes to make the remaining parts of the movie palindromic.

You are given a list $$$s$$$ of $$$n$$$ non-empty strings of length at most $$$3$$$, representing the scenes of Mihai's movie.

A subsequence of $$$s$$$ is called awesome if it is non-empty and the concatenation of the strings in the subsequence, in order, is a palindrome.

Can you help Mihai check if there is at least one awesome subsequence of $$$s$$$?

A palindrome is a string that reads the same backward as forward, for example strings "z", "aaa", "aba", "abccba" are palindromes, but strings "codeforces", "reality", "ab" are not.

A sequence $$$a$$$ is a non-empty subsequence of a non-empty sequence $$$b$$$ if $$$a$$$ can be obtained from $$$b$$$ by deletion of several (possibly zero, but not all) elements.

Input:

The first line of the input contains a single integer $$$t$$$ ($$$1 \le t \le 100$$$) — the number of test cases. The description of test cases follows.

The first line of each test case contains a single integer $$$n$$$ ($$$1 \le n \le 10^5$$$) — the number of scenes in the movie.

Then follows $$$n$$$ lines, the $$$i$$$-th of which containing a single non-empty string $$$s_i$$$ of length at most $$$3$$$, consisting of lowercase Latin letters.

It is guaranteed that the sum of $$$n$$$ over all test cases does not exceed $$$10^5$$$.

Output:

For each test case, print "YES" if there is an awesome subsequence of $$$s$$$, or "NO" otherwise (case insensitive).

Sample Input:

6
5
zx
ab
cc
zx
ba
2
ab
bad
4
co
def
orc
es
3
a
b
c
3
ab
cd
cba
2
ab
ab

Sample Output:

YES
NO
NO
YES
YES
NO

Note:

In the first test case, an awesome subsequence of $$$s$$$ is $$$[ab, cc, ba]$$$

Informação

Provedor Codeforces

Código CF1628B