771 - Jewels and Stones

771. Jewels and Stones

Problem Statement:

You're given strings jewels representing the types of stones that are jewels, and stones representing the stones you have. Each character in stones is a type of stone you have. You want to know how many of the stones you have are also jewels.

Letters are case sensitive, so "a" is considered a different type of stone from "A".

Example 1:

Input: jewels = "aA", stones = "aAAbbbb"
Output: 3

Example 2:

Input: jewels = "z", stones = "ZZ"
Output: 0

Constraints:

• 1 <= jewels.length, stones.length <= 50
• jewels and stones consist of only English letters.
• All the characters of jewels are unique.

Solution:

Java

public int numJewelsInStones(String jewels, String stones) {
  int res = 0;
  for (char stone : stones.toCharArray())
    for (char jewel : jewels.toCharArray())
      if (stone == jewel)
        res++;
  return res;
}

...