Lintcode 1038. Jewels and Stones (Easy) (Python)

Jewels and Stones

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
Example 1:

Input: J = “aA”, S = “aAAbbbb”
Output: 3
Example 2:

Input: J = “z”, S = “ZZ”
Output: 0

Code:

class Solution:
    """
    @param J: the types of stones that are jewels
    @param S: representing the stones you have
    @return: how many of the stones you have are also jewels
    """
    def numJewelsInStones(self, J, S):
        # Write your code here
        dict = collections.Counter(J)
        cnt = 0
        for i in S:
            if dict[i]:
                cnt+=1
        return cnt