771. Jewels and Stones

题目网址：https://leetcode.com/problems/jewels-and-stones/description/
大意：就是定义一个String J，这个String里面的每个character都是一种宝石，再给你一堆石头String S，让你找到这堆石头里面的每个宝石。比较简单

class Solution:
    def numJewelsInStones(self, J, S):
        """
        :type J: str
        :type S: str
        :rtype: int
        """
        i = 0
        for Jitem in J:
            for Sitem in S:
                if Jitem == Sitem:
                    i += 1
        return i

a = Solution()
print (a.numJewelsInStones('aA','aAAbbbb'))

其实就是两层for循环，还有更简单的写法

def numJewelsInStones2(self,J,S):
        return sum(s in J for s in S)