python找到连续不重复最长英文串
Python实现简单查找最长子串功能示例本文实例讲述了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：
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 printLongest 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：
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# -*- 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Falsedef IsStrIncre(s): for cnt in range(len(s) - 1): if len(s) == 1: return False elif s[cnt] > s[cnt+1]: return False return Trues = 'abajsiesnwdw'# example codesubstr = ''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 = Falseprint 'Longest substring in alphabetical order is: ' + substr |
运行结果：
Longest substring in alphabetical order is: ajs
希望本文所述对大家Python程序设计有所帮助。
原文链接：https://blog.csdn.net/dazuo01/article/details/20283619