3 задача

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

namespace _03.Period
{
    class Program
    {
        static void Main(string[] args)
        {

            Console.WriteLine("Broi chisla: ");
            int n = int.Parse(Console.ReadLine());
            int[] nums = new int[n];
            int[] period = new int[n];

            for (int i = 0; i < n; i++)
            {
                nums[i] = int.Parse(Console.ReadLine());
            }
            // 3, 1, 2, 3, 1, 2, 3
            int times = 0;
            int skip = 0;
            for (int i = 0; i < n; i++)
            {
                int cur = nums[i];
                if (nums.Count(nm => nm == cur) > 1)
                {
                    period[0] = cur;
                    break;
                }
                else
                {
                    skip++;
                }
            }
            for (int i = 1 + skip; i < n; i++)
            {
                if (nums[i] != period[0])
                {
                    period[i - skip] = nums[i];
                }
                else
                {
                    break;
                }
            }
            bool did = false;
            bool end = false;

            for (int i = 0 + skip; i < n;)
            {
                for (int j = 0; j < period.Count(p => p != 0); j++)
                {
                    if (nums[i] == period[j])
                    {
                        did = true;
                        if (i + 1 >= n)
                        {
                            end = true;
                            if (period.Count(p => p != 0) > 1 && nums[i] == period[0])
                            {
                                did = false;
                            }
                            break;
                        }
                    }
                    else
                    {
                        did = false;
                        break;
                    }
                    i++;
                }
                if (did)
                {
                    times++;
                    if (end)
                    {
                        break;
                    }
                }
                else
                {
                    break;
                }
            }

            Console.WriteLine(times);
        }
    }
}