uniqueness 2.6 fixed, C#

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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) {
            
            
        }
        
        public static void newDivQ() {
        {
            Random rand = new Random();
            
            List<string> divQ = new List<string>();
            //List<int> divisor = new List<int>();
            List<string> quotient = new List<string>();
            int num = 20;
            int count =0;
            while (divQ.Count()<num) {
                int a = rand.Next(2,101);
                int b = rand.Next(2,11);
                int c = a/b;
                
                if (a%b==0 && a/b<=10) {
                    
                    if (divQ.Count()==0) { // 1st quotient
                    
                        string q = Convert.ToString(a)+"\\div"+Convert.ToString(b)+"="+Convert.ToString(c);
                        divQ.Add(q);
                        string substring = divQ[divQ.Count-1].Substring(divQ[divQ.Count-1].IndexOf("=")+1);
                        quotient.Add(substring);
                        Console.WriteLine("divQ count{0}",divQ.Count);
                        Console.WriteLine("quotient count{0}",quotient.Count);
                        
                        
                        
                        foreach (var obj in divQ) Console.WriteLine("\n"+obj);
                        foreach (var obj in quotient) Console.WriteLine(obj);
                        Console.WriteLine();
                    }
                    
                    else if (divQ.Count()==1 && !divQ.Contains(Convert.ToString(a)+"\\div"+Convert.ToString(b)+"="+Convert.ToString(c))) { // 1st quotient
                    
                        string q = Convert.ToString(a)+"\\div"+Convert.ToString(b)+"="+Convert.ToString(c);
                        divQ.Add(q);
                        string substring = divQ[divQ.Count-1].Substring(divQ[divQ.Count-1].IndexOf("=")+1);
                        if (substring.Equals(quotient[divQ.Count-2])) { //if quotient is equal to previous quotient
                            
                            divQ.Remove(q);
                        }
                        else { // if not equal (ie. unique), add the quotient to the substring
                            
                            quotient.Add(substring);
                        }
                        Console.WriteLine("----\ndivQ count{0}",divQ.Count);
                        Console.WriteLine("quotient count{0}",quotient.Count+"\n");
                        
                        Console.WriteLine("last quotient "+quotient[divQ.Count-2]);
                        Console.WriteLine("current quotient "+quotient[divQ.Count-1]);
                        Console.WriteLine("substring "+substring);
                        
                        Console.WriteLine();
                        
                        foreach (var obj in divQ) Console.WriteLine(obj);
                        foreach (var obj in quotient) Console.WriteLine(obj);
                        Console.WriteLine();
                    }
                    
                    else if (divQ.Count()==2 && !divQ.Contains(Convert.ToString(a)+"\\div"+Convert.ToString(b)+"="+Convert.ToString(c))) { // 1st quotient
                    
                        string q = Convert.ToString(a)+"\\div"+Convert.ToString(b)+"="+Convert.ToString(c);
                        divQ.Add(q);
                        string substring = divQ[divQ.Count-1].Substring(divQ[divQ.Count-1].IndexOf("=")+1);
                        List<string> subQuotient = quotient.GetRange(quotient.Count()-2,2);
                        
                        if (!UniqueInList(substring,subQuotient)) { //if quotient is equal to one of previous 2 quotients (NOT unique)
                            
                            divQ.Remove(q);
                        }
                        else { // if not equal (ie. unique), add the quotient to the substring
                            
                            quotient.Add(substring);
                        }
                        Console.WriteLine("----\ndivQ count{0}",divQ.Count);
                        Console.WriteLine("quotient count{0}",quotient.Count+"\n");
                        
                        foreach (var obj in subQuotient) Console.Write(obj+" ");
                        Console.WriteLine("\n2nd last quotient "+quotient[divQ.Count-3]);
                        Console.WriteLine("last quotient "+quotient[divQ.Count-2]);
                        Console.WriteLine("current quotient "+quotient[divQ.Count-1]);
                        Console.WriteLine("substring "+substring);
                        
                        Console.WriteLine();
                        foreach (var obj in divQ) Console.WriteLine(obj);
                        foreach (var obj in quotient) Console.WriteLine(obj);
                        Console.WriteLine();
                    }
                    
                    else if (divQ.Count()>=3 && !divQ.Contains(Convert.ToString(a)+"\\div"+Convert.ToString(b)+"="+Convert.ToString(c))) { // 1st quotient
                    
                        string q = Convert.ToString(a)+"\\div"+Convert.ToString(b)+"="+Convert.ToString(c);
                        divQ.Add(q);
                        string substring = divQ[divQ.Count-1].Substring(divQ[divQ.Count-1].IndexOf("=")+1);
                        List<string> subQuotient = quotient.GetRange(quotient.Count()-3,3);
                        
                        if (!UniqueInList(substring,subQuotient)) { //if quotient is equal to one of previous 3 quotients (NOT unique)
                            
                            divQ.Remove(q);
                        }
                        else { // if not equal (ie. unique), add the quotient to the substring
                            
                            quotient.Add(substring);
                        }
                        Console.WriteLine("----\ndivQ count{0}",divQ.Count);
                        Console.WriteLine("quotient count{0}",quotient.Count+"\n");
                        
                        foreach (var obj in subQuotient) Console.Write(obj+" ");
                        Console.WriteLine("\n3rd last quotient "+quotient[divQ.Count-4]);
                        Console.WriteLine("2nd last quotient "+quotient[divQ.Count-3]);
                        Console.WriteLine("last quotient "+quotient[divQ.Count-2]);
                        Console.WriteLine("current quotient "+quotient[divQ.Count-1]);
                        Console.WriteLine("substring "+substring);
                        Console.WriteLine();
                        foreach (var obj in divQ) Console.WriteLine(obj);
                        foreach (var obj in quotient) Console.WriteLine(obj);
                        Console.WriteLine();
                    }
                }
                
            }
            
            
            /* for (int i =0; i<100; i++) {
                
                list.Add(rand.Next(1,40));
            
            }*/
            
            
            
        }
                             
                          
        public static bool UniqueInList(string n, List<string> t) {
            
            int count = 0;
            for (int i=0; i<t.Count(); i++) {

if (!n.Equals(t[i])) count++;
            }
            
            if (count.Equals(t.Count())) return true;
            else return false;
            
        }
        
        
        public static bool Unique(List<string> 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;
            
            
                  
        }
            
    }

}

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Compilation time: 0,19 sec, absolute running time: 0,16 sec, cpu time: 0,09 sec, average memory usage: 15 Mb, average nr of threads: 3, absolute service time: 0,37 sec