合并两个排序的链表

输入两个递增排序的链表，合并这两个链表并使新链表中的节点仍然是递增排序的。

示例1：

输入：1->2->4, 1->3->4
输出：1->1->2->3->4->4

class ListNode {
    int val;
    ListNode next;

    ListNode(int x) {
        val = x;
    }
}

public　class Solution {

    public static void main(String[] args) {
        ListNode l1 = new ListNode(1);
        l1.next = new ListNode(2);
        l1.next.next = new ListNode(4);

        ListNode l2 = new ListNode(1);
        l2.next = new ListNode(3);
        l2.next.next = new ListNode(4);


        Solution solution = new Solution();
        ListNode listNode = solution.mergeTwoLists(l1, l2);
        while (listNode!=null){
            System.out.println(listNode.val);
            listNode = listNode.next;
        }
    }

    public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
        ListNode newHead = new ListNode(-1);
        ListNode newHeadPoint = newHead;
        while (l1!=null || l2!=null){

            if (l1==null){
                newHeadPoint.next = l2;
                break;
            }
            if (l2==null) {
                newHeadPoint.next = l1;
                break;
            }


            if (l1.val < l2.val){
                newHeadPoint.next = l1;
                newHeadPoint = newHeadPoint.next;
                l1 = l1.next;
                continue;
            } else {
                newHeadPoint.next = l2;
                newHeadPoint = newHeadPoint.next;
                l2 = l2.next;
                continue;
            }
        }



        return newHead.next;
    }
}