Reverse Words in a String II

题目描述

do it in-place, no extra space

解题方法

这里的输入也不同了，是一个list, 这样才可以in-place

Solution

class Solution(object):
    def reverseWords(self, s):
        """
        :type s: a list of 1 length strings (List[str])
        :rtype: nothing
        """
        self.reverse(s, 0, len(s) - 1)

        first = 0
        for i in range(len(s)):
            if s[i] == " ":
                self.reverse(s, first, i-1)
                first = i + 1
            elif i == len(s) - 1:
                self.reverse(s, first, i)

    def reverse(self, s, start, end):
        while start < end:
            s[start], s[end] = s[end], s[start]
            start += 1
            end -= 1

Reference