1.Description

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.

You may assume the two numbers do not contain any leading zero, except the number 0 itself.

Follow up: What if you cannot modify the input lists? In other words, reversing the lists is not allowed.

Example:

Input: (7 -> 2 -> 4 -> 3) + (5 -> 6 -> 4) Output: 7 -> 8 -> 0 -> 7 解读 输入为两个list，分别包含了两个数字的各个位上的数字，输出为两个数字的和，返回仍然以list的方式，期间不能使输入倒置

2.Solution

#@未来战士biubiu #Time:O(n),Space:O(n)#不太会算.. class Solution(object): def addTwoNumbers(self, l1, l2): """ :type l1: ListNode :type l2: ListNode :rtype: ListNode """ str1=str2=str3='' while l1!=None: str1+=str(l1.val) l1=l1.next while l2!=None: str2+=str(l2.val) l2=l2.next str3=str(int(str1)+int(str2)) p=a=ListNode(0) for num in str3: p.next=ListNode(int(num)) p=p.next return a.next

有点暴力了，把链表中的数字提取出来化成字符串，然后转换成int相加，然后转换成ListNode