https://leetcode-cn.com/problems/add-to-array-form-of-integer/
    [制卡]

    1. /**
    2. * 989. 数组形式的整数加法
    3. */
    4. export function addToArrayForm(num: number[], k: number): number[] {
    5.     let ks = `${k}`.split('')
    6.     let l1 = num.length - 1;
    7.     let l2 = ks.length - 1;
    8.     let list: number[] = []
    9.     let carry = 0
    10.     while (l1 >= 0 || l2 >= 0) {
    11.         let x = l1 < 0 ? 0 : num[l1];
    12.         let y = l2 < 0 ? 0 : Number(ks[l2]);
    13.         let sum = x + y + carry;
    14.         list.push(sum % 10)
    15.         carry = Math.floor(sum / 10); // 余数取整；
    16.         l1--;
    17.         l2--;
    18.     }
    19.     if (carry) list.push(carry)
    20.     return  list.reverse()
    21. }
    /*
自己写的 错误解法
function addToArrayForm(num: number[], k: number): number[] {
  // 取最短的长度
  let ks = `${k}`.split('')
  let lenB = num.length >= ks.length
  let len = lenB ? ks.length : num.length
  let resbefor = lenB ? num.slice(0, -len) : []
  let numArr = num.slice(-len)
  let kArr = ks.slice(-len)
  let res = []
  let ten = 0 // 是否满 10
  for (let i = len - 1; i >= 0; i--) {
    const sum = Number(numArr[i]) + Number(kArr[i]) + ten
    if(i > 0){
      if (sum < 10) {
        res[i] = sum
        ten = 0
      } else{
        ten = 1
        res[i] = sum % 10
      }
    }
    // 处理最后一个
    if(i===0){
      if(sum<10){
        res[i] = sum
        ten = 0
      }else {
        res[i] = 0
        return resbefor.concat(res)
      }
    }
  }

  return resbefor.concat(res)
};
console.log(addToArrayForm([9,9,9,9,9,9,9,9,9,9], 1));
*/