Finding longest substring in alphabetical order

Question

EDIT: I am aware that a question with similar task was already asked in SO but I\'m interested to find out the problem in this specific piece of code. I am

Answer 1

I came up with this solution

def longest_sorted_string(s):
    max_string = ''
    for i in range(len(s)):
        for j in range(i+1, len(s)+1):
            string = s[i:j]
            arr = list(string)
            if sorted(string) == arr and len(max_string) < len(string):
                max_string = string
    return max_string