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.

Java代码如下：

package com.example.demo;

public class JewelsAndStones {

    public static int numJewelsInStones(String J, String S) {
        int count = 0;
        for(int i = 0; i < S.length(); i++){
            if (J.indexOf(S.charAt(i))!=-1){
                count++;
            }
        }
        return count;
    } 

    public static void main(String[] args) {
        System.out.println(numJewelsInStones("aA","aAAbbbb"));
        System.out.println(numJewelsInStones("z","ZZ"));

    }

}