Compute a number of distinct values in an array.
- Difficulty Level: Easy
- Question URL: https://app.codility.com/programmers/lessons/6-sorting/distinct/
- Time Complexity:
Question:
Write a function
class Solution { public int solution(int[] A); }
that, 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.
Write an efficient algorithm for the following assumptions:
- N is an integer within the range [0..100,000];
- each element of array A is an integer within the range [−1,000,000..1,000,000].
Solution:
Solution to Codility's Distinct problem which is from the Codility Lesson 6: Sorting and, is solved in Java 8 with 100% performance and correctness scores. The goal here is to compute a number of distinct values in an array. You can find the question of this Distinct problem in the Codility website.
package Codility.Lesson6;
import java.util.*;
public class Distinct {
public static void main(String[] args) {
int[] in2 = { 4, 5, 6 };
int result = solution(in2);
System.out.println(result);
}
public static int solution(int[] A) {
// write your code in Java SE 8
Set set = new HashSet();
for (int i = 0; i < A.length; i++) {
set.add(A[i]);
}
return set.size();
}
}