// The problem to solve: Given two arrays of integers, assuming values between 1 and 100,000, find the lowest nonzero nonnegative number that does not exist in either array, and print it.

using System;
using System.Linq;
using System.Collections.Generic;

namespace HelloWorld
{
    class Program
    {
        static void Main(string[] args)
        {
            // These are the arrays with the numbers:
            int[] array1 = { 2, 4, 3, 201, 1003, 1, 6, 6, 7, -20, 10000, -30, 200303 };
            int[] array2 = { 10, -2, 1000, 5, -300, -200, -1000, 100, 10000, -2042, 32021 };

            // These three methods make array2 bigger to hold array1, combines both arrays into array2, and then the method sorts array2 numerically.
            Array.Resize(ref array2, array2.Length + array1.Length + 10);
            Array.Copy(array1, 0, array2, array1.Length, array1.Length);
            Array.Sort(array2);

            // Eliminate the edge case of repeated values by calling a linq function to eliminate duplicates.
            IEnumerable<int> array = array2.Distinct();

            // x is an integer that holds the current checked value between 1 and 100,000. In my code, it can only go up.
            int x = 1;

            // Iterates through every element in array2, which contains both array1 and array2.
            foreach (int i in array)
            {
                // i being the current element in array2, this line skips over every element that is below 1.
                if (i < 1) continue;

                // if i does not equal the current checked value, then we have the answer. It prints the answer and leaves the program.
                if (i != x)
                {
                    Console.WriteLine(x);
                    return;
                }

                // Increase x and check the next number in the array.
                x++;

            }
        }
    }
}