Mark321

const isEqual = (n) => {
  n = n.toString().split('').map(el => +el)
  for(var i = 0; i < n.length; i++) {
   if(n[i] > n[i+1]) return false
 }
 return true
}

function findAll(n, k) {
  const res = []
  for(let i = Number('1'+'0'.repeat(k-1)); i < Number('1'+'0'.repeat(k)); i++) {
    const equal = isEqual(i)
    if(equal) {
      const val = i.toString().split('').map(el => +el).reduce((acc,c) => acc+c, 0)
      if(n === val && equal) res.push(i)
    }
  }
  if(res.length === 0) return []
  return [res.length, String(res[0]), String(res[res.length-1])]
}