0557-Reverse-Words-in-a-String-III.py

'''
Given a string, you need to reverse the order of characters in each word within a sentence while still preserving whitespace and initial word order.

Example 1:
Input: "Let's take LeetCode contest"
Output: "s'teL ekat edoCteeL tsetnoc"
Note: In the string, each word is separated by single space and there will not be any extra space in the string.
'''

class Solution:
    def reverseString(self, sub, start, end):
        while start < end:
            sub[start], sub[end] = sub[end], sub[start]
            start += 1
            end -= 1
    
    def reverseWords(self, s: str) -> str:
        s = list(s)
        start = 0
        for i, char in enumerate(s):
            if char == ' ':
                self.reverseString(s, start, i - 1)
                start = i + 1
            if i == len(s) - 1:
                self.reverseString(s, start, i)
        
        return ''.join(s)