python - 按字母顺序查找最长的子串

Question

我有在另一个主题上找到的这段代码，但它按连续字符而不是按字母顺序对子字符串进行排序。如何按字母顺序更正它？它打印出 lk，我想打印 ccl。谢谢

ps:我是python初学者

s = 'cyqfjhcclkbxpbojgkar'
from itertools import count

def long_alphabet(input_string):
    maxsubstr = input_string[0:0] # empty slice (to accept subclasses of str)
    for start in range(len(input_string)): # O(n)
        for end in count(start + len(maxsubstr) + 1): # O(m)
            substr = input_string[start:end] # O(m)
            if len(set(substr)) != (end - start): # found duplicates or EOS
                break
            if (ord(max(sorted(substr))) - ord(min(sorted(substr))) + 1) == len(substr):
                maxsubstr = substr
    return maxsubstr

bla = (long_alphabet(s))
print "Longest substring in alphabetical order is: %s" %bla

Answer 1

s = 'cyqfjhcclkbxpbojgkar'
r = ''
c = ''
for char in s:
    if (c == ''):
        c = char
    elif (c[-1] <= char):
        c += char
    elif (c[-1] > char):
        if (len(r) < len(c)):
            r = c
            c = char
        else:
            c = char
if (len(c) > len(r)):
    r = c
print(r)