python求两个链表组成的数字的和

 1 class ListNode:
 2     def __init__(self, x):
 3         self.val = x
 4         self.next = None
 5 
 6     def addTwoNumbers(self, l1, l2):
 7         """
 8         :type l1: ListNode
 9         :type l2: ListNode
10         :rtype: ListNode
11         """
12         val_sum = l1.val + l2.val
13         list_node = ListNode(val_sum % 10)
14         a = val_sum // 10
15         node = list_node
16         while True:
17             try:
18                 l1 = l1.next
19             except:
20                 pass
21             try:
22                 l2 = l2.next
23             except:
24                 pass
25             if not l1 and not l2:
26                 break
27             elif not l1:
28                 l1_val = 0
29                 l2_val = l2.val
30             elif not l2:
31                 l2_val = 0
32                 l1_val = l1.val
33             else:
34                 l1_val = l1.val
35                 l2_val = l2.val
36             val_sum = l1_val + l2_val + a
37             temp_node = ListNode(val_sum % 10)
38             node.next = temp_node
39             node = temp_node
40             a = val_sum // 10
41         if a != 0:
42             node.next = ListNode(a)
43         return list_node