LeetCode 771. Jewels and Stones

題目

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

解法思維

跑迴圈比對

var numJewelsInStones = function(jewels, stones) {
            let c=0
            for (const jew of jewels) {
                for (const ston of stones) {
                    if(jew==ston){
                        c++
                    }
                }

            }
            return c
};

先解構再用filter()篩選

var numJewelsInStones = function(jewels, stones) {
    let s=[...stones].filter((item)=>jewels.includes(item))
    return s.length
};