---------------🎈🎈题目链接🎈🎈-------------------

解法1 完整程序书写kama 倒序输出+每个区间倒序输出

时间复杂度O(N)
空间复杂度O(1)

import java.util.Arrays;
import java.util.Scanner;

class Main{
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);
        int k = scanner.nextInt();
        String str = scanner.next();
        
        char[] ch = str.toCharArray();
        // 倒序输出
        int left = 0;
        int right = ch.length-1;
        while(left < right){
            ch[left] ^= ch[right];
            ch[right] ^= ch[left];
            ch[left] ^= ch[right];
            left++;
            right--;
        }
        
        // 每个区间再倒叙输出
        left = 0;
        right = k-1;
        while(left < right){
            ch[left] ^= ch[right];
            ch[right] ^= ch[left];
            ch[left] ^= ch[right];
            left++;
            right--;
        }
        
        left = k;
        right = ch.length-1;
        while(left < right){
            ch[left] ^= ch[right];
            ch[right] ^= ch[left];
            ch[left] ^= ch[right];
            left++;
            right--;
        }
        
        System.out.println(ch);
    }
    
}