LeetCode-2-add-two-numbers | 两数相加

题目链接

• leetcode中国

解题思路

/**
 * Definition for singly-linked list.
 * type ListNode struct {
 *     Val int
 *     Next *ListNode
 * }
 */
func addTwoNumbers(l1 *ListNode, l2 *ListNode) *ListNode {
    //先考虑特殊情况
    if l1 == nil && l2 == nil {
        return nil
    }
    if l1 == nil {
        return l2
    }
    if l2 == nil {
        return l1
    }
    
    sum := l1.Val + l2.Val
    nextNode := addTwoNumbers(l1.Next, l2.Next)
    if sum < 10 {
        return &ListNode{ Val: sum, Next: nextNode }
    } else {
        tempNode := &ListNode{
            Val: 1,
            Next: nil,
        }
        return &ListNode{
            Val: sum - 10,
            Next: addTwoNumbers(nextNode, tempNode),
        }
    }
}