题目描述：

LeetCode 541. Reverse String II

Given a string and an integer k, you need to reverse the first k characters for every 2k characters counting from the start of the string. If there are less than k characters left, reverse all of them. If there are less than 2k but greater than or equal to k characters, then reverse the first k characters and left the other as original.

Example:

Input: s = "abcdefg", k = 2
Output: "bacdfeg"

Restrictions:

1. The string consists of lower English letters only.
2. Length of the given string and k will in the range [1, 10000]

题目大意：

给定一个字符串和一个整数k，每2k个字符翻转前k个字符。如果剩余字符不足k个，则全部翻转。如果剩余字符在k到2k之间，则翻转前k个字符，剩余字符保持原样。

约束条件：

1. 字符串只包含小写英文字母。
2. 给定字符串长度和k在范围[1, 10000]之间。

解题思路：

字符串模拟

Python代码：

class Solution(object):
    def reverseStr(self, s, k):
        """
        :type s: str
        :type k: int
        :rtype: str
        """
        ans = ''
        round = int(math.ceil(len(s) / (2.0 * k)))
        for x in range(round):
            ans += s[x * 2 * k : (x * 2 + 1) * k][::-1] 
            ans += s[(x * 2 + 1) * k : (x * 2 + 2) * k]
        return ans

 

本文链接：http://bookshadow.com/weblog/2017/03/12/leetcode-reverse-string-ii/
请尊重作者的劳动成果，转载请注明出处！书影博客保留对文章的所有权利。

如果您喜欢这篇博文，欢迎您捐赠书影博客： ，查看支付宝二维码