两数相加

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

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Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8
Explanation: 342 + 465 = 807.

实现

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const addTwoNumbers = function(l1, l2) {

const fakeHead = new ListNode(-1);
let currentNode = fakeHead;
let carry = 0;

while(l1 || l2 || carry){
let sum = carry;
if(l1){
sum += l1.val;
l1 = l1.next;
}
if(l2){
sum += l2.val;
l2 = l2.next;
}
carry = parseInt(sum / 10);
currentNode.next = new ListNode(sum % 10);
currentNode = currentNode.next;
}

return fakeHead.next;
};