Problem
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.
Solution
/**
* Definition for singly-linked list.
* function ListNode(val) {
* this.val = val;
* this.next = null;
* }
*/
/**
* @param {ListNode} l1
* @param {ListNode} l2
* @return {ListNode}
*/
var addTwoNumbers = function(l1, l2) {
var carry = 0;
var sum = 0;
var head = new ListNode(0);
var now = head;
var a = l1;
var b = l2;
while (a !== null || b !== null) {
sum = (a ? a.val : 0) + (b ? b.val : 0) + carry;
carry = Math.floor(sum / 10);
now.next = new ListNode(sum % 10);
now = now.next;
a = a ? a.next : null;
b = b ? b.next : null;
}
if (carry) now.next = new ListNode(carry);
return head.next;
};
Explain:
nope.
Complexity:
- Time complexity : O(max(m,n)).
- Space complexity : O(max(m,n)).