Distinct.java

import java.util.Set;
import java.util.HashSet;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(int[] A) {
        Set<Integer> distincts = new HashSet<>();
        for (int i: A) {
            distincts.add(i);
        }
        return distincts.size();
    }
}