JewelsAndStones771.java

/**
 * 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.
 */

public class JewelsAndStones771 {
    public int numJewelsInStones(String J, String S) {
        boolean[] map = new boolean[256];
        for (char c: J.toCharArray()) {
            map[c] = true;
        }
        int res = 0;
        for (char c: S.toCharArray()) {
            if (map[c]) res++;
        }
        return res;
    }
}