[LeetCode] Jewels and Stones

1.문제

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".

영어 알파벳 각각이 stone 의 종류를 나타내는 stones 문자열이 주어지고 jewels 문자열이 주어질 때 stone 중 jewles 인 stone의 개수를 리턴하는 문제이다.

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.

2.풀이

1. stones를 반복문을 돌면서 jewels 문자열에 현재 stone 이 포함되어 있는지 체크한다.

/**
 * @param {string} jewels
 * @param {string} stones
 * @return {number}
 */
const numJewelsInStones = function (jewels, stones) {
  let count = 0;
  // stones 에서 jewels에 포함되어 있는 stone이면 count 를 1 증가시킨다
  stones.split("").forEach((stone) => {
    if (jewels.includes(stone)) {
      count++;
    }
  });

  return count;
};

3.결과