蓝桥杯 基础练习 之 FJ的字符串

问题描述

　　FJ在沙盘上写了这样一些字符串：
　　A1 = “A”
　　A2 = “ABA”
　　A3 = “ABACABA”
　　A4 = “ABACABADABACABA”
　　… …
　　你能找出其中的规律并写所有的数列AN吗？

输入格式

　　仅有一个数：N ≤ 26。

输出格式

　　请输出相应的字符串AN，以一个换行符结束。输出中不得含有多余的空格或换行、回车符。

样例输入

3

样例输出

ABACABA

 

算法实现：

import java.util.Scanner;
public class Main {
	public static int c;
	public static String[] strings = {"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"};
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		c = sc.nextInt();
		String string = "";
		f(0, "");
	}
	
	public static void f(int index,String str){
		if(index != c){
			str = str + strings[index] +str;
			f(index+1, str);
		}else{
			System.out.println(str);
		}
	}

}