LeetCode 771: 宝石与石头 Jewels and Stones
题目: 给定字符串 J 代表石头中宝石的类型,和字符串 S 代表你拥有的石头。 S 中每个字符代表了一种你拥有的石头的类型,你想知道你拥有的石头中有多少是宝石。 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. J 中的字母不重复, J 和 S 中的所有字符都是字母。字母区分大小写,因此 "a" 和 "A" 是不同类型的石头。 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" . 示例 1: 输入: J = "aA", S = "aAAbbbb" 输出: 3 示例 2: 输入: J = "z", S