Problem #2
Add Two Numbers
problem details
problem
2
title
Add Two Numbers
short 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.
Problem Statement
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.My solution
/**
* Definition for singly-linked list.
* public class ListNode {
* public int val;
* public ListNode next;
* public ListNode(int x) { val = x; }
* }
*/
public class Solution {
public ListNode AddTwoNumbers(ListNode l1, ListNode l2) {
return AddTwoNumbers(l1, l2, 0);
}
private ListNode AddTwoNumbers(ListNode l1, ListNode l2, int carryOver)
{
int l1Value = l1?.val ?? 0;
int l2Value = l2?.val ?? 0;
int sum = l1Value + l2Value + carryOver;
if (sum == 0 && l1 == null && l2 == null)
{
return null;
}
else
{
ListNode currentNode = new ListNode(sum % 10);
currentNode.next = AddTwoNumbers(l1?.next, l2?.next, sum / 10);
return currentNode;
}
}
}