Permutation PUB

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

namespace Exam
{
    class Program
    {
        static IEnumerable<IEnumerable<T>> GetPermutations<T>(IEnumerable<T> list, int length)
        {
            if (length == 1) return list.Select(t => new T[] { t });

            return GetPermutations(list, length - 1)
                .SelectMany(t => list.Where(e => !t.Contains(e)),
                    (t1, t2) => t1.Concat(new T[] { t2 }));
        }


        static void Main()
        {
            int n = int.Parse(Console.ReadLine());

            IEnumerable<IEnumerable<int>> result =
    GetPermutations(Enumerable.Range(1, n), n);

            var res = result.ToList();

            for (int i = 0; i < res.Count; i++)
            {
                string output = string.Empty;
                int counter = 0;
                foreach (var item in res[i])
                {
                    if (counter == res.Count - 1)
                    {
                        output += item;
                    }
                    else
                    {
                        output += item + " ";
                    }
                }
                Console.WriteLine(output);
            }
        }
    }
}