1038. 珠宝和石头

/*
* 输入: J = “aA”, S = “aAAbbbb” 输出: 3
* 输入: J = “z”, S = “ZZ” 输出: 0
*/
public static int numJewelsInStones(String J, String S) {
// Write your code here
int res = 0;
for (int i = 0; i < J.length(); i++) {
char j = J.charAt(i);
for (int k = 0; k < S.length(); k++) {
char s = S.charAt(k);
if(s==j) {
res++;
}
}
}
return res;
}