数据结构-栈，队列，链表，树

 

 

 

 

 

 

 

 

 

class ListNode {
    constructor(key = null, next = null) {
        this.key = key;
        this.next = next;
    }

    push(next) {
        this.next = next;
        return next;
    }

    reverse() {
        if (this.key !== null) {
            console.log("不是NIL");
            return;
        }
        var Nil = this;
        var pre = this.next;
        var cur = pre.next;
        pre.next = null;
        while (cur !== null) {
            console.log("pre:", pre.key, "cur:", cur.key);
            var next = cur.next;
            cur.next = pre;
            pre = cur;
            cur = next;
        }
        Nil.next = pre;
        return Nil;
    }

    toStirng() {
        var cur = this;
        while (cur != null) {
            if (cur.next) {
                console.log("the key of this ListNode is: ", cur.key, "the next of this ListNode is: ", cur.next.key);

            } else {
                console.log("the key of this ListNode is: ", cur.key, "the next of this ListNode is: null");
            }
            cur = cur.next;
        }
    }
}


var NIL = new ListNode();

var first = new ListNode(1);

var second = new ListNode(2);

var third = new ListNode(3);


NIL.push(first).push(second).push(third);

var temp = NIL.next;

NIL.reverse().toStirng();

 

 

 这是前序遍历