leetcode刷題記錄 easy(1) 771.Jewels and Stones

英文題目：

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".

Example 1:

Input: J = "aA", S = "aAAbbbb"
Output: 3

Example 2:

Input: J = "z", S = "ZZ"
Output: 0

 Note:

• S and J will consist of letters and have length at most 50.
• The characters in J are distinct.

 

中文題目解釋：

解析：

可以使用String類的indexOf方法，

public int indexOf(int ch): 返回指定字符在字符串中第一次出現處的索引，如果此字符串中沒有這樣的字符，則返回 -1。

結果提交：

class Solution {
    public int numJewelsInStones(String J, String S) {
        char[] sc=S.toCharArray();
        int i=0;
        for (char s:sc) {
                if(J.indexOf(s)!=-1){
                    i++;
                }
        }
        return i;
    }
}