from math import factorial
def lexicographic_permutation_order(s):
   my_sequence = list(s)
   for _ in range(factorial(len(my_sequence))):
      print(''.join(my_sequence))
      next = next_in_permutation(my_sequence)

      if next is None:
         my_sequence.reverse()
      else:
         my_sequence = next

def next_in_permutation(my_sequence):
   if len(my_sequence) == 0:
      return None
   next = next_in_permutation(my_sequence[1:])
   if next is None:
      my_sequence[1:] = reversed(my_sequence[1:])
      q = 1
      while q < len(my_sequence) and my_sequence[0] > my_sequence[q]:
         q += 1
      if q == len(my_sequence):
         return None
      my_sequence[0], my_sequence[q] = my_sequence[q], my_sequence[0]
      return my_sequence
   else:
      return [my_sequence[0]] + next

my_input = input('输入一个字符串：')
print("字符串是：")
print(my_input)
print("正在调用方法...")
lexicographic_permutation_order(my_input)

输入一个字符串：hey
字符串是：
hey
正在调用方法...
hey
hye
yeh
yhe
hey
hye