codeforces#P1796B. Asterisk-Minor Template
Asterisk-Minor Template
Description
You are given two strings $a$ and $b$, consisting of lowercase Latin letters.
A template $t$ is string, consisting of lowercase Latin letters and asterisks (character '*'). A template is called asterisk-minor if the number of asterisks in it is less than or equal to the number of letters in it.
A string $s$ is said to be matching a template $t$ if you can replace each asterisk in $t$ with a string of lowercase Latin letters (possibly, an empty string) so that it becomes equal to $s$.
Find an asterisk-minor template such that both $a$ and $b$ match it, or report that such a template doesn't exist. If there are multiple answers, print any of them.
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 string $a$ ($1 \le |a| \le 50$, where $|a|$ is the length of $a$), consisting of lowercase Latin letters.
The second line contains a string $b$ ($1 \le |b| \le 50$), consisting of lowercase Latin letters.
For each testcase, output "NO", if there doesn't exist an asterisk-minor template that both $a$ and $b$ match. Otherwise, print "YES" in the first line and the template in the second line. If there are multiple answers, print any of them.
A template should consist only of lowercase Latin letters and asterisks (character '*'). The number of asterisks should be less than or equal to the number of letters.
Input
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 string $a$ ($1 \le |a| \le 50$, where $|a|$ is the length of $a$), consisting of lowercase Latin letters.
The second line contains a string $b$ ($1 \le |b| \le 50$), consisting of lowercase Latin letters.
Output
For each testcase, output "NO", if there doesn't exist an asterisk-minor template that both $a$ and $b$ match. Otherwise, print "YES" in the first line and the template in the second line. If there are multiple answers, print any of them.
A template should consist only of lowercase Latin letters and asterisks (character '*'). The number of asterisks should be less than or equal to the number of letters.
6
aaab
zzzb
codeforces
atcoder
codeforces
tokitlx
aaaa
aaaaaa
abcd
abcd
c
f
YES
*b
YES
*co*
NO
YES
a*a*a*a
YES
abcd
NO
Note
In the first testcase, for a template "*b", you can replace the only asterisk with "aaa" to get "aaab" (which is equal to $a$) or with "zzz" to get "zzzb" (which is equal to $b$).
In the third testcase, a template "*o*" is not asterisk-minor, as it contains more asterisks than letters. There are no asterisk-minor templates that both $a$ and $b$ match.
In the fourth testcase, for a template "a*a*a*a", you can replace all asterisks with empty strings to get "aaaa" (which is equal to $a$) or two of them with "a" and two of them with an empty string to get "aaaaaa" (which is equal to $b$).
In the fifth testcase, there are no asterisks in a template "abcd", so only "abcd" can match it (which is coincidentally both $a$ and $b$).