蓝桥杯Java 递归倒置字符数组 算法提高

 

Java递归倒置字符数组 算法提高

关键还是字符串数组转 char数组，递归注意递归次数就可以

import java.util.Scanner;
public class test3 {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String[] string=sc.nextLine().split(" ");
		char[] arr = new char[Integer.valueOf(string[0])];//String[0]为字符数组长度
		arr = string[1].toCharArray();
		aa(arr, 0);
	}

	private static void aa(char[] arr, int ii) {
		if (ii >= arr.length-1-ii) {
			System.out.println();
			for (int i = 0; i < arr.length; i++) {
				System.out.print(arr[i]);
			}
			return;
		} else {
			char c = arr[ii];//交换首尾字符
			arr[ii] = arr[arr.length - 1 - ii];
			arr[arr.length - 1 - ii] = c;
			
			for (int i = 0; i < arr.length; i++) {
				System.out.print(arr[i]);
			}
			System.out.println();
			aa(arr, ii + 1);
		}
	}
}