[LeetCode&Python] Problem 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:

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

class Solution(object):

    def reverseStr(self, s, k):

        """

        :type s: str

        :type k: int

        :rtype: str

        """

        n=len(s)

        i=0

        ans=''

        while i<n:

            if i+k-1>=n:

                ans+=(s[i:])[::-1]

                break

            elif i+2*k-1>=n:

                ans+=(s[i:i+k])[::-1]+s[i+k:]

                break

            else:

                ans+=(s[i:i+k])[::-1]+s[i+k:i+2*k]

                i=i+2*k

        return ans

巴特西

[LeetCode&Python] Problem 541. Reverse String II

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