#P1628B. Peculiar Movie Preferences
Peculiar Movie Preferences
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.
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 $10^5$.
For each test case, print "YES" if there is an awesome subsequence of $s$, or "NO" otherwise (case insensitive).
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).
Samples
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
YES
NO
NO
YES
YES
NO
Note
In the first test case, an awesome subsequence of $s$ is $[ab, cc, ba]$