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.
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”.
Jwill consist of letters and have length at most 50.
- The characters in
還滿簡單的一題，連想都不太需要想。題目翻譯成白話文是這樣的，給定兩個字串 J 與 S，檢查字串 S 中有多少字元屬於字串 J。不用管它寶石還石頭啦 XD
這題用暴力法逐一搜索就好了，為了改善時間複雜度，我將 J 放入 HashSet 中
程式碼可以進一使用 map 來化簡