INNOVATUBE small test

Solution.java

//package com.example;

public class Solution {
    public static void main(String[] args) {
        int array[] = new int[4];
        array[0] = 2;
        array[1] = 3;
        array[2] = 1;
        array[3] = 5;
        System.out.println(Solution.solution(array)); //it should return 4
    }

    public static int solution(int[] firstArray) {
        int i;
        //create the second array to compare
        int[] secondArray = new int[firstArray.length + 1];
        for (i = 0; i < firstArray.length; i++) {
            secondArray[i] = firstArray[i] + 1;
        }
        //find distinct element
        int missingElement = 0;

        for (i = 0; i < firstArray.length; i++) {
            missingElement += (firstArray[i] - secondArray[i]);
        }
        return Math.abs(missingElement - secondArray[i]);
       
    }
}