Add-Two-Numbers.md

Add-Two-Numbers

给你两个链表表示两个非负数字。数字是反向存储的并且每个节点包含一个数字。添加两个数字并返回一个链表（如果有进位则加1）。

Example

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

code

/**
 * 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 List = new ListNode(0);
    var head = List;
    var sum = 0;
    var carry = 0;
    while(l1!==null||l2!==null||sum>0){
        if(l1!==null){
            sum = sum + l1.val;
            l1 = l1.next;
        }
        if(l2!==null){
            sum = sum + l2.val;
            l2 = l2.next;
        }
        if(sum>=10){
            carry = 1;
            sum = sum - 10;
        }
        head.next = new ListNode(sum);
        head = head.next;
        sum = carry;
        carry = 0;
    }
    return List.next;
};