前端算法-leecode-2 两数相加（链表）

var addTwoNumbers = function(l1, l2) {
    let dummy = new ListNode;
    let cur = dummy;
    let temp = 0;
    while(l1 !==null || l2 !==null){
        let sum = 0;
        if(l1 !==null){
            sum += l1.val;
            l1=l1.next;
        }
        if(l2 !==null){
            sum+=l2.val;
            l2 = l2.next;
        }
        sum += temp;
        cur.next =  new ListNode (sum%10);
        temp = Math.floor(sum/10);
        cur= cur.next;
    }
    if(temp>0){
        cur.next = new ListNode(temp)
    }
    return dummy.next;
    };