Solution.py

class Solution:
    def reverseWords(self, s: List[str]) -> None:
        def reverse(i: int, j: int):
            while i < j:
                s[i], s[j] = s[j], s[i]
                i, j = i + 1, j - 1

        i, n = 0, len(s)
        for j, c in enumerate(s):
            if c == " ":
                reverse(i, j - 1)
                i = j + 1
            elif j == n - 1:
                reverse(i, j)
        reverse(0, n - 1)