上班摸鱼刷算法-Java-hot100-[21]合并两个有序链表

//将一个链表插入到另一个链表中
class Solution {
    public ListNode mergeTwoLists(ListNode list1, ListNode list2) {
        if (list1 == null) {
            return list2;
        }
        if (list2 == null) {
            return list1;
        }
        return list1.val < list2.val ? mergeLists(list1, list2) : mergeLists(list2, list1);

    }

    public ListNode mergeLists(ListNode list1, ListNode list2) {
        ListNode head = list1;
        while (list1 != null && list1.next != null && list2 != null) {
            if (list2.val >= list1.val && list2.val < list1.next.val) {
                ListNode listNode2 = list2.next;
                list2.next = list1.next;
                list1.next = list2;
                list1 = list1.next;
                list2 = listNode2;
                continue;
            }
            list1 = list1.next;
        }
        if (list2 != null) {
            list1.next = list2;
        }
        return head;
    }
}