771. Jewels and Stones

딕셔너리를 사용한 해시 테이블로 풀 수 있음.

import collections

class Solution:
    def numJewelsInStones(self, jewels: str, stones: str) -> int:
        counter = collections.Counter(stones)
        answer = 0
        
        for j in jewels:
            answer += counter[j]
            
        return answer

https://leetcode.com/problems/jewels-and-stones/