0002.add-two-numbers.md

0002.Add-Two-Numbers

Description

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.

Tags: Linked List, Math

题意

以链表表示一个数，低位在前，高位在后，所以题中的例子就是 342 + 465 = 807.

题解

思路 1

直接模拟计算就好

func addTwoNumbers(l1 *ListNode, l2 *ListNode) *ListNode {
    node := &ListNode{Val: 0, Next: nil}
    n1, n2, tmp := l1, l2, node
    sum := 0

    for n1 != nil || n2 != nil {
        sum /= 10
        if n1 != nil {
            sum += n1.Val
            n1 = n1.Next

        }
        if n2 != nil {
            sum += n2.Val
            n2 = n2.Next
        }
        tmp.Next = &ListNode{Val: sum % 10}
        tmp = tmp.Next
    }
    if sum/10 != 0 {
        tmp.Next = &ListNode{Val: 1}
    }
    return node.Next
}

思路 2

思路 2 ```go

```

结语

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