Python实现简单查找最长子串功能示例-创新互联

本文实例讲述了Python实现简单查找最长子串功能。分享给大家供大家参考，具体如下：

十年的威宁网站建设经验，针对设计、前端、开发、售后、文案、推广等六对一服务，响应快，48小时及时工作处理。成都全网营销的优势是能够根据用户设备显示端的尺寸不同，自动调整威宁建站的显示方式，使网站能够适用不同显示终端，在浏览器中调整网站的宽度，无论在任何一种浏览器上浏览网站，都能展现优雅布局与设计，从而大程度地提升浏览体验。创新互联从事“威宁网站设计”,“威宁网站推广”以来，每个客户项目都认真落实执行。

题目选自edX公开课 MITx: 6.00.1x Introduction to Computer Science and Programming 课程 Week2 的Problem Set 1的第三题。下面是原题内容。

Assume s is a string of lower case characters.

Write a program that prints the longest substring of s in which the letters occur in alphabetical order. For example, ifs = 'azcbobobegghakl', then your program should print

Longest substring in alphabetical order is: beggh
In the case of ties, print the first substring. For example, if s = 'abcbcd', then your program should print

Longest substring in alphabetical order is: abc
For problems such as these, do not include raw_input statements or define the variable s in any way. Our automated testing will provide a value of s for you - so the code you submit in the following box should assume s is already defined. If you are confused by this instruction, please review L4 Problems 10 and 11 before you begin this problem set.

代码如下：

# -*- coding:utf-8 -*-
#! python2
#判断一个字符串内的字母是否是按字母表顺序
# 如IsStrIncre('abbcdg') 返回 True
# IsStrIncre('abbadg') 返回 False
# 如果只有一个字符，也返回False
def IsStrIncre(s):
  for cnt in range(len(s) - 1):
    if len(s) == 1:
      return False
    elif s[cnt] > s[cnt+1]:
      return False
  return True
s = 'abajsiesnwdw'# example code
substr = ''
for length in range(1, len(s)+1):
  firstflag = True # a flag to remember the first string that satisfied the requirements
           # and ignore the strings satisfied the requirements but appeared after
  for cnt in range(len(s)-length+1):
    if IsStrIncre(s[cnt: cnt+length]):
      if firstflag:
        substr = s[cnt: cnt+length]
        firstflag = False
print 'Longest substring in alphabetical order is: ' + substr

网页名称：Python实现简单查找最长子串功能示例-创新互联
浏览路径：http://bjjierui.cn/article/dsgois.html