Hi,
The problem description is in the comments above the solution below.

The problem belongs to Codility, you can try out it yourself on their platform.
 

import java.util.Arrays;

/**
 * given an array A consisting of N integers, returns the number of distinct values in array A.
 *
 * For example, given array A consisting of six elements such that:
 *  A[0] = 2    A[1] = 1    A[2] = 1
 *  A[3] = 2    A[4] = 3    A[5] = 1
 *
 * the function should return 3, because there are 3 distinct values appearing in array A, namely 1, 2 and 3.
 */
public class Distinct {
    public int solution(int[] A) {
        if(A.length <=1) return A.length;
        Arrays.sort(A);
        int count=1;
        for(int i=1;i < A.length;i++){
            if(A[i] != A[i-1]){
                count++;
            }
        }
        return count;
    }
}