Find the longest substring in alphabetical order

Question

I have this code that I found on another topic, but it sorts the substring by contiguous characters and not by alphabetical order. How do I correct it for alphabetical order

Answer 1

input_str = "cyqfjhcclkbxpbojgkar"
length = len(input_str) # length of the input string
iter = 0
result_str = '' # contains latest processed sub string
longest = '' # contains longest sub string alphabetic order 
while length > 1: # loop till all char processed from string
    count = 1
    key = input_str[iter] #set last checked char as key 
    result_str += key # start of the new sub string
    for i in range(iter+1, len(input_str)): # discard processed char to set new range
      length -= 1
      if(key <= input_str[i]): # check the char is in alphabetic order 
        key = input_str[i]
        result_str += key # concatenate the char to result_str
        count += 1
      else:
        if(len(longest) < len(result_str)): # check result and longest str length
          longest = result_str # if yes set longest to result
        result_str = '' # re initiate result_str for new sub string
        iter += count # update iter value to point the index of last processed char
        break

    if length is 1: # check for the last iteration of while loop
        if(len(longest) < len(result_str)):
          longest = result_str

print(longest);