771.Jewels and Stones¶

771.Jewels and Stones¶

Tags: Easy Hash Table

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

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

Note:

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

Answer:

class Solution {
public:
    int numJewelsInStones(string J, string S) {
        multiset<char> ms(S.begin(), S.end());
        int result = 0;

        for (auto i : J){
            result += ms.count(i);
        }

        return result;
    }
};