541. Reverse String II

solution541.py

# https://leetcode.com/problems/reverse-string-ii/description/

class Solution(object):
    def reverseStr(self, s, k):
        """
        :type s: str
        :type k: int
        :rtype: str
        """
        half_k = k//2
        
        str_ptr = 0
        
        s_list = list(s)
        
        while str_ptr < len(s):
            temp_head = str_ptr
            temp_tail = str_ptr + k - 1
            if temp_tail >= len(s):
                temp_tail = len(s) - 1
            while temp_head < temp_tail:
                s_list[temp_head], s_list[temp_tail] = s_list[temp_tail], s_list[temp_head]
                temp_head += 1
                temp_tail -= 1
            
            str_ptr += (2 * k)
            
        return ''.join(s_list)