496 next greater element i

def (self, findNums, nums):
  """
  :type findNums: List[int]
  :type nums: List[int]
  :rtype: List[int]
  """
  d = {}
  st = []
  r = []
  for x in nums:
      while len(st) and st[-1]<x:
          d[st.pop()] = x
      st.append(x)
  for y in findNums:
      r.append(d.get(y,-1))
  return r