day13 合并两个排序的链表(leetcode剑指Offer25)

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

限制：
0 <= 链表长度 <= 1000

class Solution:
    def mergeTwoLists(self, l1: ListNode, l2: ListNode) -> ListNode:
        new = ListNode(0)
        cur = new
        while l1 and l2:
            if l1.val <= l2.val:
                cur.next = l1
                l1 = l1.next
            else:
                cur.next = l2
                l2 = l2.next
            cur = cur.next
        while l1:
            cur.next = l1
            l1 = l1.next
            cur = cur.next
        while l2:
            cur.next = l2
            l2 = l2.next
            cur = cur.next
        return new.next