Write a java program to find the smallest positive integer not present in an array

I do find this question while practicing #Java_Programming on #codility. There are many solution to this question but I think the best one I have came across is using hashSet. It's a simple combination than using array login so thought of sharing it.

Before proceeding ahead in order to understand this #problem_statement better here are few examples:

given A = [1, 3, 6, 4, 1, 2], the function should return 5.

Given A = [1, 2, 3], the function should return 4.

Given A = [−1, −3], the function should return 1.

Logic:

We are storing all the element of the input array in #HashSet and we will define int smallint =1; we will use while loop to loop all the element of an array and compare it with smallint =1 value. if the value is equal to smallint =1 then we are incrementing value by 1 and print the result or we will print smallint =1

#Java_Code

package Others;

import java.util.*;

public class smallestpossibleNumberInArray {
	
	public static int solution(int[]  a){
		
		HashSet<Integer> hashSet = new HashSet<Integer>();
		int smallint =1;
		
		for (int i = 0; i < a.length; i ++){
			hashSet.add(a [i]);
		}
		
		while (hashSet.contains(smallint)){
			smallint ++;
		}
		
		return smallint;
	
	}
	

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		
		System.out.println("Please enter the array");
		
		Scanner sc = new Scanner(System.in);
		
		int [] A =  new int [5];
		
		for (int i = 0; i < A.length; i ++){
			System.out.println("please enter the number");
			
			A[i] = sc.nextInt();
		}
		sc.close();
		
		// output of the function
		
		System.out.println("NextSmallestpositiveNumber in an array is " +solution(A) );
		
	}

}

#output

Please enter the array
please enter the number
-22
please enter the number
0
please enter the number
-11
please enter the number
-2
please enter the number
1
NextSmallestpositiveNumber in an array is 2

#Java #Smallest_Next_Positive_Number_In_an_Array #Selenium #Hashset