Score : $200$ points
We will call a string that can be obtained by concatenating two equal strings an even string.
For example, xyzxyz
and aaaaaa
are even, while ababab
and xyzxy
are not.
You are given an even string $S$ consisting of lowercase English letters. Find the length of the longest even string that can be obtained by deleting one or more characters from the end of $S$. It is guaranteed that such a non-empty string exists for a given input.
Input is given from Standard Input in the following format:
$S$
Print the length of the longest even string that can be obtained.
abaababaab
6
abaababaab
itself is even, but we need to delete at least one character.abaababaa
is not even.abaababa
is not even.abaabab
is not even.abaaba
is even. Thus, we should print its length, $6$.xxxx
2
xxx
is not even.xx
is even.abcabcabcabc
6
The longest even string that can be obtained is abcabc
, whose length is $6$.
akasakaakasakasakaakas
14
The longest even string that can be obtained is akasakaakasaka
, whose length is $14$.