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
     */
    public ArrayList<String> getSolution (int n) {
        ArrayList<String> steps = new ArrayList<>();
        // write code here
        Haroi(steps, n, "left", "right", "mid");

        return steps;
    }

    public void Haroi(ArrayList<String> steps, int n, String start, String des, String util) {
        if (n == 1) {
            steps.add("move from " + start + " to " + des);
            System.out.println("move from " + start + " to " + des);
            return;
        }
        Haroi(steps, n - 1, start, util, des);
        Haroi(steps, 1, start, des, util);
        Haroi(steps, n - 1, util, des, start);
    }
}