算法004

描述

从尾到头反过来打印出每个结点的值。

例子

Input:
	1 -> 2 -> 3
Output:
	3 2 1

思路

方法一：递归调用 方法二：使用栈

代码

class Node {
    private Node next;
    private int val;

    public Node(Node next, int val) {
        this.next = next;
        this.val = val;
    }

    public Node getNext() {
        return next;
    }

    public void setNext(Node next) {
        this.next = next;
    }

    public int getVal() {
        return val;
    }

    public void setVal(int val) {
        this.val = val;
    }
}

public class Question004 {
    public static void main(String[] args) {
        Node node3 = new Node(null, 3);
        Node node2 = new Node(node3, 2);
        Node node1 = new Node(node2, 1);
        Node node = node1;
		//使用栈
        Stack<Integer> stack = new Stack<>();
        while (node != null) {
            stack.push(node.getVal());
            node = node.getNext();
        }

        while (!stack.empty()) {
            System.out.println(stack.pop());
        }
        //递归调用
//        printListFromTailToHead(node1);
    }
    public static void printListFromTailToHead(Node list) {
        if (list.getNext() != null) {
            printListFromTailToHead(list.getNext());
        }
        System.out.println(list.getVal());
    }
}