for Codility PermMissingElem

PermMissingElem.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace PermMissingElem
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] A = { 2, 3, 5, 4 };
            Solution sol = new Solution();
            int result = sol.solution(A);
            Console.WriteLine("result is: " + result.ToString());
        }
    }

    public class Solution
    {
        public int lastElement = -1;
        public int solution(int[] input)
        {
            if(input.Length==0)
            {
                return 1;
            }

            int arraySize = input.Length;
            int missedElement = -1;
            for (int i = 0; i < arraySize; i++)
            {

                if (input[i] - 1 == arraySize)
                {
                    input[i] = -1;
                    lastElement = arraySize;
                }
                else if (input[i] - 1 != i)
                {
                    MoveELement(input, i);
                }
            }
            Console.WriteLine("print array");
            for (int i = 0; i < arraySize; i++)
            {
                if (input[i] == -1)
                {
                    missedElement = i + 1;
                }
                Console.WriteLine(input[i]);
            }
            if (missedElement == -1)
            {
                missedElement = arraySize + 1;
            }
            return missedElement;
        }
        public void MoveELement(int[] input, int index)
        {
            bool stopFlag = false;
            int currentValue = input[index];
            input[index] = -1;
            while (!stopFlag)
            {
                if (currentValue - 1 == input.Length)
                {
                    lastElement = currentValue;
                    stopFlag = true;
                    Console.WriteLine("assign to last element");
                }
                else if (input[currentValue - 1] == -1)
                {
                    input[currentValue - 1] = currentValue;
                    stopFlag = true;
                }
                else
                {
                    int temp = input[currentValue - 1];
                    input[currentValue - 1] = currentValue;
                    currentValue = temp;
                    Console.WriteLine("not current value is " + currentValue.ToString());
                }
                Console.WriteLine("stop flag is " + stopFlag.ToString());
                //System.Threading.Thread.Sleep(1000);
            }

        }
    }
}