reverse-words-in-a-string.py

'''
P.S: Given an input string s, reverse the order of the words.
A word is defined as a sequence of non-space characters. The words in s will be separated by at least one space.
Return a string of the words in reverse order concatenated by a single space.
Note that s may contain leading or trailing spaces or multiple spaces between two words. 
The returned string should only have a single space separating the words. Do not include any extra spaces.
'''

#Solution:
import re
class Solution(object):
    def reverseWords(self, s):
        """
        :type s: str
        :rtype: str
        """
        s = re.sub(' +', ' ', s)
        new_s = ''
        li = s.split(' ')
        li=li[::-1]
        for x in li:
            new_s+=x
            new_s+=' '            
        return new_s.strip()

#Solution2:
class Solution(object):
    def reverseWords(self, s):
        """
        :type s: str
        :rtype: str
        """
        s = " ".join(s.split())
        new_s = ''
        li = s.split(' ')
        li=li[::-1]
        for x in li:
            new_s+=x
            new_s+=' '            
        return new_s.strip()