【LeetCode with Python】 Reverse Words in a String

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原题页面：https://oj.leetcode.com/problems/reverse-words-in-a-string/
题目类型：字符串，两指针问题
难度评价：★
本文地址：http://blog.csdn.net/nerv3x3/article/details/3465547

Given an input string, reverse the string word by word.

For example,
Given s = "the sky is blue",
return "blue is sky the".

click to show clarification.

Clarification:

• What constitutes a word?
  A sequence of non-space characters constitutes a word.
• Could the input string contain leading or trailing spaces?
  Yes. However, your reversed string should not contain leading or trailing spaces.
• How about multiple spaces between two words?
  Reduce them to a single space in the reversed string.

反转一句话中的单词。注意题中还要求去除首尾可能存在的空白字符，词与词之间也要去除多余空白字符，而只留一个空白。

class Solution:    # @param s, a string    # @return a string    def reverseWords(self, s):        len_s = len(s)        if len_s < 1:            return s        index_right = len_s - 1        new_s = ""        while index_right >= 0:            while index_right >= 0 and ' ' == s[index_right]:                index_right -= 1            end_index = index_right            while index_right >= 0 and ' ' != s[index_right]:                index_right -= 1            start_index = index_right + 1            word = s[start_index : end_index + 1] if end_index >= 0 else ""            new_s += (word + " ")        return new_s.rstrip()