Given a node from a cyclic linked list which has been sorted, write a function to insert a value into the list such that it remains a cyclic sorted list. The given node can be any single node in the list. Return the inserted new node.

解题：

需要考虑listnode 为null， 单个node， 2-2-2-2-2-2等特殊情况。

做一次do while 去check是否有222222类似循环

/**
 * Definition for ListNode
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) {
 *         val = x;
 *         next = null;
 *     }
 * }
 */
public class Solution {
    /**
     * @param node a list node in the list
     * @param x an integer
     * @return the inserted new list node
     */
    public ListNode insert(ListNode node, int x) {
        // Write your code here
        if(node == null){
             ListNode newNode = new ListNode(x);
             newNode.next = newNode;
            return newNode;
        }

        if(node.next == null || node.next == node){
            ListNode newNode = new ListNode(x);

             newNode.next = node;
             node.next = newNode;
             return node;

        }
        ListNode point = node;
        ListNode prev = null;
        do {
            prev = point;
            point = point.next;
            if (prev.val <= x && point.val >= x) {
                break;
            }
            if ((prev.val > point.val) && (x > prev.val || x < point.val)) {
                break;
            }
        } while (point != node);
        ListNode newNode = new ListNode(x);
        newNode.next = point;
        prev.next = newNode;
        return newNode;
    }
}