_771.java

package com.fishercoder.solutions;

import java.util.HashSet;
import java.util.Set;

/**
 * 771. 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.
 */

public class _771 {
  public static class Solution1 {
    public int numJewelsInStones(String J, String S) {
      Set<Character> set = new HashSet<>();
      for (char c : J.toCharArray()) {
        set.add(c);
      }
      int count = 0;
      for (char c : S.toCharArray()) {
        if (set.contains(c)) {
          count++;
        }
      }
      return count;
    }
  }
}