Python解决LeetCode第二题时class类报错

Question

来源：LeetCode第二题

# Definition for singly-linked list.
class ListNode(object):
    def __init__(self, x):
        self.val = x
        self.next = None
 
class Solution(object):
    def addTwoNumbers(self, l1, l2):
        """
        :type l1: ListNode
        :type l2: ListNode
        :rtype: ListNode
        """
        if self.getLength(l1) < self.getLength(l2): #保证l1永远比l2更长
            l1, l2 = l2, l1
            
        head = l1   
        while(l2):#执行加法
            l1.val += l2.val
            l1 = l1.next
            l2 = l2.next
        
        p = head
        while(p):#处理进位
            if p.val > 9:
                p.val -= 10
                if p.next:
                    p.next.val += 1
                else:
                    p.next = ListNode(1)
            p = p.next
                    
        return head
        
        
    def getLength(self, l):#计算链表长度
        length = 0
        while(l):
            length += 1
            l = l.next
        return length
T = Solution()
print(T.addTwoNumbers([1,8,9,6],[9,8,7]))

报错：

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
Input In [4], in <cell line: 44>()
     42 T = Solution()
     43 #T.getLength()
---> 44 print(T.addTwoNumbers([1,8,9,6],[9,8,7]))

Input In [4], in Solution.addTwoNumbers(self, l1, l2)
      8 def addTwoNumbers(self, l1, l2):
      9     """
     10     :type l1: ListNode
     11     :type l2: ListNode
     12     :rtype: ListNode
     13     """
---> 14     if self.getLength(l1) < self.getLength(l2): #保证l1永远比l2更长
     15         l1, l2 = l2, l1
     17     head = l1   

Input In [4], in Solution.getLength(self, l)
     38 while(l):
     39     length += 1
---> 40     l = l.next
     41 return length

AttributeError: 'list' object has no attribute 'next'

刚刚练习LeetCode第二题的时候，代码一直上面这个错误，请问一下友友们应该怎么解决啊？

Answer 1

至少你应该这样去建你的l1,l2

T = Solution()

lt = [1,8,9,6]
l1 = ListNode(lt[0])
lt1 = l1 
for i in lt[1:]:
    lt1.next = ListNode(i)
    lt1 = lt1.next
lt = [9, 8, 7]
l2 = ListNode(lt[0])
lt2 = l2 
for i in lt[1:]:
    lt2.next = ListNode(i)
    lt2 = lt2.next

print(T.addTwoNumbers(l1,l2))