LeetCode771 宝石与石头

• 题目
• 解题

题目

解题

// javascript
var numJewelsInStones = function(jewels, stones) {
    const jewelSet = new Set(Array.from(jewels));
    let cnt = 0;
    for (const stone of stones) {
        if (jewelSet.has(stone) === true) {
            cnt++;
        }
    }
    return cnt;
};

高级写法：使用 reduce 函数

// javascript
var numJewelsInStones = function(jewels, stones) {
    const jewelsSet = new Set(jewels.split(''));
    return stones.split('').reduce((prev, val) => {
        return prev + jewelsSet.has(val);
    }, 0);
};