面試題16：反轉鏈表

劍指Offer面試題16：反轉鏈表（JS實現）

題目描述：定義一個函數，輸入一個鏈表的頭結點，反轉該鏈表並輸出反轉後鏈表的頭結點

    function LinkList() {
        var Node = function(element){
            this.element = element;
            this.next = null;
        }
        var head = null;

        //在尾部插入結點
        this.append = function(element) {
            var node = new Node(element),
                current;
            if(head === null) {
                head = node;
            }else{
                current = head;
                while(current.next) {
                    current = current.next;
                }
                current.next = node;
            }
        }


        //反轉鏈表
        this.ReverseList = function(){
            if(head === null) {
                return null;
            }
            var reverseHead = null,
                current = head,
                prev = null,
                next = null;
            while(current){
                //保存結點防止斷裂
                next = current.next;
                if(next === null) {
                    reverseHead = current;
                }
                current.next = prev;
                prev = current;
                current = next;
            }

            return reverseHead.element;

        }
    }

    var link = new LinkList();
    link.append(1);
    link.append(2);
    link.append(3);
    link.append(4);
    link.append(5);
    link.append(6);

    console.log(link.ReverseList());