445. Add Two Numbers II

🟧 Medium

Solution

My Solution

/**
 * Definition for singly-linked list.
 * type ListNode struct {
 *     Val int
 *     Next *ListNode
 * }
 */
func addTwoNumbers(l1 *ListNode, l2 *ListNode) *ListNode {
    nums1 := make([]int, 0, 100)
    nums2 := make([]int, 0, 100)
    for l1 != nil {
        nums1 = append(nums1, l1.Val)
        l1 = l1.Next
    }

    for l2 != nil {
        nums2 = append(nums2, l2.Val)
        l2 = l2.Next
    }
    maxL := max(len(nums1), len(nums2))
    if len(nums1) != maxL {
        nums1 = append(make([]int, maxL-len(nums1)), nums1...)
    }

    if len(nums2) != maxL {
        nums2 = append(make([]int, maxL-len(nums2)), nums2...)
    }

    carry := 0
    var head *ListNode

    for i := maxL - 1; i >= 0; i-- {
        num := nums1[i] + nums2[i] + carry
        carry = num / 10

        node := &ListNode{Val: num % 10}
        node.Next = head
        head = node
    }

    if carry != 0 {
        node := &ListNode{Val: carry}
        node.Next = head
        head = node
    }
    if head == nil {
        return &ListNode{}
    }

    return head
}

result

Leetcode: link