text: # DESCRIPTION
  # You're given strings J representing the types of stones that are jewels,
  # and S representing the stones you have.  Each character in S is a type of stone you have.
  # You want to know how many of the stones you have are also jewels.
  # The letters in J are guaranteed distinct, and all characters in J and S are letters.
  # Letters are case sensitive, so "a" is considered a different type of stone from "A".
  
  # EXAMPLE 1:
  # Input: J = "aA", S = "aAAbbbb"
  # Output: 3
  
  # EXAMPLE 2:
  # Input: J = "z", S = "ZZ"
  # Output: 0
  
  
  class Solution:
      '''
      Time: O(J+S), J is the len of char array, S is len of char array
      Space: O(J), turns the array of jewels into set data structure
      '''
  
      def numJewelsInStones(self, J: str, S: str) -> int:
          counter = 0
          # set saves on memory from dict
          jewels = set(J)
  
          for item in S:
              if item in jewels:
                  counter += 1
  
          return counter
  