题解 | #字符串加解密#

import string
# 不需要手写ABCD... 1234...
low_char_list = string.ascii_lowercase
upp_char_list = string.ascii_uppercase
number_list = string.digits


def encode_ch(char):
    if char in number_list:
        return number_list[(number_list.index(char)+1)%len(number_list)]
    else:
        next_char = low_char_list[(low_char_list.index(char.lower())+1)%len(low_char_list)]
        if not char.isupper():
            return next_char.swapcase()
        else:
            return next_char

def decode_ch(char):
    if char in number_list:
        return number_list[(number_list.index(char)-1)%len(number_list)]
    else:
        next_char = low_char_list[(low_char_list.index(char.lower())-1)%len(low_char_list)]
        if not char.isupper():
            return next_char.swapcase()
        else:
            return next_char
    
def encode_str(input_str):
    encode_str = ""
    for i in input_str:
        encode_str += encode_ch(i)
    return encode_str

def decode_str(input_str):
    decode_str = ""
    for i in input_str:
        decode_str += decode_ch(i)
    return decode_str

tag = 1
while 1:
    try:
        input_str = input()
        if tag %2 != 0:
            print(encode_str(input_str))
        else:
            print(decode_str(input_str))
        tag +=1
    except:
        break