常见的链表操作

链表操作是算法基本功之一，最近看算法，做了几个链表比较基础的题目。大家看这些题目，拿着纸笔画一画，思路瞬间清晰。之后希望持续更新~~。

        //定义链表        function Node (value) {            this.value = value;            this.next = null;        }        //把数组转化成链表        function arrToList (arr) {            var head = new Node(arr[0]);            var node = head            for(var i=1; i < arr.length; i++) {                var onode = new Node(arr[i]);                node.next = onode;                node = node.next;            }            return head;        }        //获取链表长度        function getLength (list) {            var length = 0;            while (list != null) {                list = list.next;                length = length + 1;            }            return length;        }        //算法1：翻转链表        function reverseList (head) {            var p = null;            while (head!=null) {                var q = head.next;                head.next = p;                p = head;                 head = q;                console.log(q);            }            return p;        }        //算法2: 判断链表是否有环        function hasCircle (head) {            if(head == null || head.next == null) {                return false;            }            var fast = head.next;            var slow = head;            while (fast != slow) {                if (fast == null || fast.next == null) {                    return false;                }                fast = fast.next.next;                slow =slow.next;            }            return true;        }        /*var list1 = arrToList([1,2,3,4,5,6,7]);        var list2 = arrToList([8,9,10]);        var list3 =list.next;        list.next.next = list2;        list2.next.next.next = list3;*/        //算法3: 链表相加求和        function addList (list1,list2) {            var carry = 0;            var head = new Node(0);            var point = head;            while (list1!=null && list2!=null) {                //num,carry的取值是重点                var num = (list1.value + list2.value + carry);                point.next =  new Node(num % 10);                carry = parseInt(num/10);                list1 = list1.next;                list2 = list2.next;                point = point.next;            }            while (list1!=null) {                var num = (list1.value + carry);                point.next =  new Node(num % 10);                carry = parseInt(num/10);                list1 = list1.next;                point = point.next;            }            while (list2!=null) {                var num = (list2.value + carry);                point.next =  new Node(num % 10);                carry = parseInt(num/10);                list2 = list2.next;                point = point.next;            }            while (carry !=0) {                var num = carry;                point.next =  new Node(num % 10);                carry = parseInt(num/10);            }            return head;        }        //算法4: 删除链表倒数第n个节点        function deleteKpoint (list,k) {            var p = list;            var q = list;            while (k > 0) {                if (list == null) {                    return null;                }                list = list.next;                k = k-1;            }            //注意这里的临界值判断            while (list.next != null) {                p = p.next;                list = list.next;            }            p.next = p.next.next;            return q;        }        //算法5: 得到链表的倒数第n个结点        function getKpoint (list,k) {            var p = list;            while (k > 0) {                if (list == null) {                    return null;                }                list = list.next;                k = k-1;            }            //注意这里的临界值判断            while (list != null) {                p = p.next;                list = list.next;            }            return p;        }        //算法6: 删除链表中重复的元素        function deleteRepeat (list) {            var p = list;            while (list.next != null) {                if (list.value == list.next.value) {                    list.next = list.next.next;                } else {                    list = list.next;                }            }            return p;        }        //算法7: 删除链表中重复元素,并删除该结点        function deleteRepeat2 (list) {            var oNode = new Node();            oNode.next = list;            list = oNode;            //下面的if判断谁的value，上面的限制条件临界值就是这个            while (list.next!=null && list.next.next!= null) {                if (list.next.value == list.next.next.value) {                    var number = list.next.value;                    while (list.next != null && list.next.value == number) {                        list.next = list.next.next;                    }                } else {                    list = list.next;                }            }            return oNode.next;        }        //算法8: 旋转链表        function rotateList(list,k) {            var length = getLength(list);            k = k % length;            var p = list;            var q = list;            while (list.next != null && k > 0) {                list = list.next;                k = k - 1;            }            while (list.next != null) {                list = list.next;                p = p.next;            }            var r = p.next;            list.next = q;            p.next = null;            return r;        }