``` # 已知二叉树 先序,中序 求后序 # 先序： 根左右 # 中序： 左根右 f1 = ["A", "B", "C", "D", "E", "F"] m1 = ["C", "B", "A", "E", "D", "F"] # 后序：C B E F D A # print(m1[3:]) def get_b(f, m): if f == [] or m == []:

##### from enum import Enum type object has no attribute ‘**getitem**‘ ```python #如果已经安装过enum #使用pip uninstall enum #然后 pip install enum34 ```

``` def Ip2long(ip_str): '''把字符串形式的IP地址转换成long int 形式''' ips=ip_str.split('.') ip_long=int(ips[3])+int(ips[2])*256+int(ips[1])*(256**2)+int(ips[0])*(256**3) return ip_long def Long2ip(ip_long): '''�

``` #! /usr/bin/env python #coding=utf-8 import ctypes,sys STD_INPUT_HANDLE = -10 STD_OUTPUT_HANDLE = -11 STD_ERROR_HANDLE = -12 # 字体颜色定义 ,关键在于颜色编码，由2位十六进制组成，分别取0~f，前一位指的是背景色，�

``` #-*-coding:utf-8-*- import threading import time import inspect import ctypes def _async_raise(tid, exctype): """raises the exception, performs cleanup if needed""" tid = ctypes.c_long(tid) if not inspect.isclass(exctype): exctype = typ

``` #coding: utf-8 import smtplib import sys from email.mime.text import MIMEText from email.header import Header def sendmail(username,password,receiver,subject,text): sender = username smtp = smtplib.SMTP() smtp.connect('smtp.126.com') smtp