LeetCode LCR 181 - 字符串中的单词反转

class Solution:
    def reverseMessage(self, message: str) -> str:
        # 先调用split()分割后再用单一空格进行字符串组合，倒序输出到列表中方便遍历
        strLst = list(' '.join(message.split())[::-1])
        sLen = len(strLst)
        head, tail = 0, sLen - 1

        # 去除前导空格（实际上可能不需要做）
        while head < sLen and strLst[head] == ' ':
            head += 1
        while tail >= 0 and strLst[tail] == ' ':
            tail -= 1
        first, second = head, head
        while first <= tail and second <= tail:
            # 利用内层循环直接让tail冲到能进行交换的地方，避免tail出了外循环后还要最后在循环外再做一次反转
            while second <= tail and strLst[second] != ' ':
                second += 1
            # 用切片法反转最优雅
            strLst[first:second] = strLst[first:second][::-1]
            first = second + 1
            second += 1
        return "".join(strLst)