两数相加

    1. const addSum = function (l1,l2) {
    2.       let head = new ListNode(-1)
    3.       const res = head
    4.       let add = 0
    5.       while(l1 || l2 || add){
    6.           let l1val = l1.val ?? 0
    7.           let l2val = l2.val ?? 0
    8.           let isAdd = l1val +  l2val + add
    9.           if(isAdd>=10){
    10.               add = 1
    11.           }else{
    12.               add = 0
    13.           }
    14.           if(l1)l1 = l1.next
    15.           if(l2)l2 = l2.next
    16.           const list = new ListNode(isAdd%10)
    17.           head.next = list
    18.           head = list
    19.       }
    20.       return res.next
    21.   }

    1 未采用new ListNode 存值
    2 未考虑 循环&add 判断