题解 | #汉诺塔问题#

import java.util.*;


public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param n int整型 
     * @return string字符串ArrayList
     */
  
  	//自定义递归函数完成问题
    public ArrayList<String> getSolution (int n) {
        // write code here
        String s1 = "left";
        String s2 = "mid";
        String s3 = "right";
        ArrayList<String> strs = new ArrayList<>();
        function(n, s1, s2, s3, strs);
        return strs;
    }

    public void function(int n, String s1, String s2, String s3, ArrayList<String> strs){
        if (n == 1) {
            strs.add("move from " + s1 + " to " + s3);
        } else {
            function(n - 1, s1, s3, s2, strs);
            strs.add("move from " + s1 + " to " + s3);
            function(n - 1, s2, s1, s3, strs);
        }
    }
}