using System;

public class Program

{

    public static void Main()

    {

        int[] nums = new int[]{ 4,5 };

        Console.WriteLine(RemoveDuplicates(ref nums,4));

        Console.WriteLine(string.Join(",",nums));

    }

    public static int RemoveDuplicates(int[] nums) {

        int repetidos = 0;

        int total = nums.Length;

        int lastIndex = 1;

        for(int i=1; i<nums.Length; i++){

            Console.WriteLine("num i: {0}  num i-1: {1}",nums[i],nums[i-1]);

            if( nums[i] != nums[i-1]){

                nums[lastIndex] = nums[i];

                lastIndex++;

            }else{

                repetidos++;

            }

        }

        return total - repetidos;

    }

    public static int RemoveDuplicates(ref int[] nums, int val) {

        int i = 0;

        int n = nums.Length;

        while (i < n) {

            if (nums[i] == val) {

                nums[i] = nums[n - 1];

                n--;

            } else {

                i++;

            }

        }

        return n;

    }

}