Python-сообщество

 s = 'arefhertyjertyaref!!'
step_1= []
test = len(s)//2
ind_for = 1
ind_append = 0
for i in range(test):
    for j in range(test + ind_for):
        step_1.append(s[j : test + j + ind_append])
    ind_for += 1
    ind_append -= 1
step_2 = []
for i in range(len(step_1)):
    if step_1[i] in step_1[i + len(step_1[i]):]:
        step_2.append(step_1[i])
if len(step_2) == 0:
    print("решения нет")
elif len(step_2) == 1:
    print(step_2)
else: # исправлено
    step_3 = [step_2[0]]
    for i in range(len(step_2)):
        if len(step_2[i]) == len(step_2[i + 1]):
            step_3.append(step_2[i + 1])
        else:
            print(step_3)
            break

   
from itertools import takewhile
  
def find_longest_substr(string):
    longest_seq = ""
    s = string
    while s:
        char = s[0]
        seq = list(takewhile(lambda i: i == char, s))
        length = len(seq)
        if length > len(longest_seq):
            longest_seq = seq
        s = s[length:]
    return "".join(longest_seq)
  
print(find_longest_substr("0111112222"))

import re
l='arefhjaref!!'
for i in range(len(l)//2, 0, -1):
        s=r"(.{"+str(i)+r",}).*?\1"
        a=re.findall(s,l)
        if a:print(str(a));break

 s = 'arefhjaref!!'
out = []
for i in range(len(s)):
    t = s[i:]
    for j in range(len(t),1,-1):
        s1,s2 = t[:j],t[j:]
        f = s2.find(s1)
        if f > 0: 
                out.append(s1)
                break
out.sort(key = lambda x: len(x),reverse=True)
print(out)