LeetCode : numJewelsInStones

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

class Solution {
    public int numJewelsInStones(String J, String S) {
        int count = 0;
        for(char c : S.toCharArray()) {
            for(char j : J.toCharArray()) {
                if(c == j) {
                    count++;
                }
            }
        }
        return count;
    }
}요

• string char loop : toCharArray();