In this Kata, you will be given a string and your task will be to return the length of the longest prefix that is also a suffix. A prefix is the start of a string while the suffix is the end of a string.  For instance, the prefixes of the string `"abcd"` are `["a","ab","abc"]`. The suffixes are `["bcd", "cd", "d"]`. You should not overlap the prefix and suffix.

```Haskell
for example:
solve("abcd") = 0, because no prefix == suffix. 
solve("abcda") = 1, because the longest prefix which == suffix is "a".
solve("abcdabc") = 3. Longest prefix which == suffix is "abc".
solve("aaaa") = 2. Longest prefix which == suffix is "aa". You should not overlap the prefix and suffix
solve("aa") = 1. You should not overlap the prefix and suffix.
solve("a") = 0. You should not overlap the prefix and suffix.
```

All strings will be lowercase and string lengths are `1 <= length <= 500`

More examples in test cases. Good luck!

Difficulty: EASY
Starter code: def solve(st):
	

Solutions:
def solve(st):
	return next((n for n in range(len(st) // 2, 0, -1) if st[:n] == st[-n:]), 0)


def solve(s):
	for i in range(len(s) // 2, 0, -1):
		if s[:i] == s[-i:]:
			return i
	return 0


solve = lambda s: len(__import__('re').match('^(.*).*\\1$', s).group(1))


def solve(st):
	i = len(st) // 2
	while i and (not st.endswith(st[0:i])):
		i -= 1
	return i


def solve(st):
	attempts = len(st) // 2
	for i in range(attempts, 0, -1):
		if st[:i] == st[-i:]:
			return i
	return 0


import math

def prefix_suffix_check(string, indexIn):
	return string[:indexIn] == string[indexIn * -1:]

def solve(initial_string):
	half_array_size = int(math.floor(len(initial_string) / 2))
	for x in range(half_array_size, 0, -1):
		if prefix_suffix_check(initial_string, x) == True:
			return x
	return 0


def solve(st):
	prefixes = set()
	sufixes = set()
	pref = ''
	suff = st[1:]
	for i in st[:-1]:
		sufixes.add(suff)
		suff = suff[1:]
		pref += i
		prefixes.add(pref)
	for i in sorted(sufixes.intersection(prefixes))[::-1]:
		if len(i) * 2 <= len(st):
			return len(i)
	return 0


def solve(st):
	return max((i for i in range(1, len(st) // 2 + 1) if st[:i] == st[-i:]), default=0)


def solve(st):
	for i in range(len(st) - 1, 0, -1):
		if not i or (len(st) >= 2 * i and st[0:i] == st[-i:]):
			return i
	return 0