ianadiwibowo/central-park

package main

import "fmt"

// 2. Add Two Numbers (Medium)
// https://leetcode.com/problems/add-two-numbers/

type ListNode struct {
    Val  int
    Next *ListNode
}

func addTwoNumbers(l1 *ListNode, l2 *ListNode) *ListNode {
    result := &ListNode{}
    r := result
    remainder := 0
    l1Ended := false
    l2Ended := false

    for {
        a := 0
        if !l1Ended {
            a = l1.Val
        }

        b := 0
        if !l2Ended {
            b = l2.Val
        }

        sum := a + b + remainder
        if sum > 9 {
            sum = sum % 10
            remainder = 1
        } else {
            remainder = 0
        }
        r.Val = sum

        if l1.Next != nil {
            l1 = l1.Next
        } else {
            l1Ended = true
        }

        if l2.Next != nil {
            l2 = l2.Next
        } else {
            l2Ended = true
        }

        if l1Ended && l2Ended && remainder == 0 {
            break
        }

        r.Next = &ListNode{}
        r = r.Next
    }

    return result
}

func printLinkedList(l *ListNode) string {
    result := fmt.Sprintf("%v", l.Val)
    for l.Next != nil {
        l = l.Next
        result = fmt.Sprintf("%v%v", result, l.Val)
    }
    return result
}