1 """ 2 You are given two non-empty linked lists representing two non-negative integers. The most significant digit comes first and each of their nodes contain a single digit. Add the two numbers and return it as a linked list. 3 You may assume the two numbers do not contain any leading zero, except the number 0 itself. 4 Follow up: 5 What if you cannot modify the input lists? In other words, reversing the lists is not allowed. 6 Example: 7 Input: (7 -> 2 -> 4 -> 3) + (5 -> 6 -> 4) 8 Output: 7 -> 8 -> 0 -> 7 9 """ 10 """ 11 与leetcode2 类似。 12 这两题都是自己做出来的 13 """ 14 class ListNode: 15 def __init__(self, x): 16 self.val = x 17 self.next = None 18 19 class Solution: 20 def addTwoNumbers(self, l1, l2): 21 num1, num2 = 0, 0 22 if l1 and not l2: 23 return l1 24 if l2 and not l1: 25 return l1 26 p1, p2 = l1, l2 #将链表l1 和 l2 转成数字num1 和num2 求和得num 27 while p1: 28 num1 = num1 * 10 + p1.val 29 p1 = p1.next 30 while p2: 31 num2 = num2 * 10 + p2.val 32 p2 = p2.next 33 num = num1 + num2 34 res = ListNode(0) #头结点 35 end = ListNode(num % 10) #尾结点 36 res.next = end 37 end.next = None 38 num = num // 10 39 while num: #从链表尾部插入当前结点cur 40 cur = ListNode(num % 10) #当前结点 41 res.next = cur 42 cur.next = end 43 end = cur 44 num = num // 10 45 return res.next