# -*- coding:utf-8 -*-

class Solution:

    def LeftRotateString(self, s, n):

        # write code here

        if len(s) <= 1:

            return s

        n = n % len(s) # 处理n>len(s)的情况

        # 思路1

        # return s[k:] + s[:k]

        # 思路2

        # return (s[:n][::-1]+s[n:][::-1])[::-1]

        # 思路2

        s = list(s)

        self.reverse(s,0,n-1)

        self.reverse(s,n,len(s)-1)

        self.reverse(s,0,len(s)-1)

        return "".join(s)

    def reverse(self, s,start,end):

        while start < end:

            s[start],s[end] = s[end],s[start]

            start += 1

            end -= 1

if __name__ == '__main__':

    result = Solution().LeftRotateString('abcXYZdef',4)

    print(result)