leetcode刷题笔记--2. Add Two Numbers

原题链接 2. Add Two Numbers
You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order 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.

Example:
Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8
Explanation: 342 + 465 = 807.

采取递归的方式实现

func addTwoNumbers(l1 *ListNode, l2 *ListNode) *ListNode {
    if l1 == nil {
        return l2
    }
    if l2 == nil {
        return l1
    }
    _sum := l1.Val + l2.Val
    res := &ListNode{Val:_sum % 10}
    res.Next = addTwoNumbers(l1.Next,l2.Next)
    if _sum >= 10 {
        res.Next = addTwoNumbers(res.Next,&ListNode{Val:1})
    }
    return res
}