LeetCode 771 Jewels and Stones 解题报告

题目要求

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".

Input: J = "aA", S = "aAAbbbb"
Output: 3​​

S and J will consist of letters and have length at most 50.The characters in J are distinct.

题目分析及思路

题目要求J中的字符都不一样，找出S中与J中字符相同的字符个数。可以用两层循环遍历两个字符串，还可引入集合进行比较。​

python代码​

class Solution:

    def numJewelsInStones(self, J, S):

        """

        :type J: str

        :type S: str

        :rtype: int

        """

        jewels = set(J)

        sum = 0

        for c in S:

            if c in jewels:

                sum += 1

        return sum