代码随想录算法训练营day8|344.反转字符串 ● 541. 反转字符串II ● 卡码网：54.替换数字

class Solution(object):
    def reverseString(self, s):
        """
        :type s: List[str]
        :rtype: None Do not return anything, modify s in-place instead.
        """
        left, right = 0, len(s)-1
        while left < right:
            s[left], s[right] = s[right], s[left]
            left += 1
            right -= 1
        return s

class Solution(object):
    def reverseStr(self, s, k):
        """
        :type s: str
        :type k: int
        :rtype: str
        """
        def reverse_substring(text):
            left, right = 0, len(text)-1
            while left < right:
                text[left], text[right] = text[right], text[left]
                left += 1
                right -= 1
            return text
        
        # 每2k距离执行一次反转
        ls = list(s)
        for i in range(0, len(ls), 2*k):
            ls[i:i+k]=reverse_substring(ls[i:i+k])
        return ''.join(ls)

class Solution:
    def change(self, s):
        lst = list(s)
        for i in range(len(lst)):
            if lst[i].isdigit():
                lst[i] = "number"
        return ''.join(lst)