uniqueness2, C# - rextester

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//Rextester.Program.Main is the entry point for your code. Don't change it.
//Compiler version 4.0.30319.17929 for Microsoft (R) .NET Framework 4.5

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

namespace Rextester
{
    public class Program
    {
        public static void Main(string[] args)
        {
            //Your code goes here
            Random rand = new Random();
            HashSet<string> divQ = new HashSet<string>();
            /*for (int i=2; i<=100; i++) {
                
                for (int j=2; j<=10; j++) {
                    
                    if (i%j==0&& i/j<=10) {
                        
                        string a = Convert.ToString(i)+"\\div"+Convert.ToString(j);
                        divQ.Add(a);
                    }
                }
            }*/
            int count=0;
            List<int> divisor = new List<int>();
            List<int> quotient = new List<int>();
            while (divQ.Count()<3) {
                int a = rand.Next(2,101);
                int b = rand.Next(2,11);
                int c = a/b;
                
                if (a%b==0 && a/b<=10) {
                    
                    if (quotient.Count()==0) { // 1st quotient
                    
                        string q = Convert.ToString(a)+"\\div"+Convert.ToString(b)+"= "+Convert.ToString(c);
                        divQ.Add(q);
                        quotient.Add(c);
                        count++;
                    }
                    else if (quotient.Count()==1 && c!=quotient[count-1]) { // 2nd quotient / if [count] and [count-1] not equal
                        string q = Convert.ToString(a)+"\\div"+Convert.ToString(b)+"= "+Convert.ToString(c);
                        divQ.Add(q);
                        quotient.Add(c);
                        count++;
                    }
                    /*
                    else if (quotient.Count()==2 && UniqueInList(c,quotient.GetRange(count-2,2))) { // 3rd quotient
                        string q = Convert.ToString(a)+"\\div"+Convert.ToString(b)+"= "+Convert.ToString(c);
                        divQ.Add(q);
                        quotient.Add(c);
                        count++;
                    }
                    /*
                    else if (quotient.Count()>3 && UniqueInList(c,quotient.GetRange(count-3,3))) {
                        string q = Convert.ToString(a)+"\\div"+Convert.ToString(b)+"= "+Convert.ToString(c);
                        divQ.Add(q);
                        quotient.Add(c);
                        count++;
                    }*/

}
                
                Console.Write(UniqueInList(c,quotient.GetRange(count-2,2)));
            }
            /* for (int i =0; i<100; i++) {
                
                list.Add(rand.Next(1,40));
            
            }*/
            
            foreach (var item in divQ)
            {
                Console.WriteLine(item);
            }
            
            
        }
                             
                          
        public static bool UniqueInList(int n, List<int> t) {
            
            int count = 0;
            for (int i=0; i<t.Count()-1; i++) {

if (n==t[i]) count++;
            }
            
                if (count == t.Count()) return true;
                else return false;
        }
        
        public static bool Unique(List<int> t){
        
            int count = 0;
            for (int i=0; i<t.Count()-1; i++){ 
                for (int j=i+1; j<t.Count(); j++) { 
                    //Console.WriteLine(i + " " + j);
                    
                    if (!t[i].Equals(t[j])){
                    
                        count++;
                    }
                       
                }
            }
            if (count.Equals(nCr(t.Count(),2))) {
                
                return true;
            }
            else return false;
        }
        
        public static int nCr(int n, int r) {
        
            return (Factorial(n)/Factorial(r))/Factorial(n-r);
        }
        
        public static int Factorial(int n) {
            
            if (n>0) {
                for (int i=n-1; i>1; i--) {

n = n*i;
                }

return n;
            }
            
            else if (n<0) throw new ArgumentOutOfRangeException("n","n should be non-zero");
                
            else return 1;
            
            
                  
        }
            
    }

}

Show compiler warnings [ + ] Show input
Compilation time: 0,19 sec, absolute running time: 0,11 sec, cpu time: 0,09 sec, average memory usage: 15 Mb, average nr of threads: 3, absolute service time: 0,33 sec