LeetCode--Python合并两个有序链表

class ListNode:
    def __init__(self, x):
        self.val = x
        self.next = None

class Solution:
    def mergeTwoLists(self, l1, l2):
        """
        :type l1: ListNode
        :type l2: ListNode
        :rtype: ListNode
        """
        newHead = ListNode(0)
        pre = newHead
        while l1 and l2:
            if l1.val<l2.val:
                pre.next = l1
                l1 = l1.next
            else:
                pre.next = l2
                l2 = l2.next
            pre = pre.next
        if l1:
            pre.next = l1
        elif l2:
            pre.next = l2
        return newHead.next
        
# 有序链表
head1 = ListNode(2)
n1 = ListNode(3)
n2 = ListNode(4)
n3 = ListNode(9)
head1.next = n1
n1.next = n2
n2.next = n3

# 有序链表
head2 = ListNode(3)
m1 = ListNode(5)
m2 = ListNode(7)
m3 = ListNode(8)
head2.next = m1
m1.next = m2
m2.next = m3

s = Solution()
res = s.mergeTwoLists(head1,head2)
while res:
    print(res.val)
    res = res.next