Add benchmarks limits

Author: ythosa

csharp/Platform.Numbers.Benchmarks/MathBenchmarks.cs

@@ -14,16 +14,28 @@ public long FactorialUsingRecursion()
             return Math.Factorial(FACTORIALTESTNUMBER);
         }
 
+        [Benchmark]
+        public long FactorialRecursionCountingArraylength()
+        {
+            return Math.FactorialRecursionCountingArraylength(FACTORIALTESTNUMBER);
+        }
+
         [Benchmark]
         public long FactorialUsingFactTree()
         {
             return Math.FactTree(FACTORIALTESTNUMBER);
         }
 
         [Benchmark]
-        public long FactorialRecursionCountingArraylength()
+        public long FactorialOnly21()
         {
-            return Math.FactorialRecursionCountingArraylength(FACTORIALTESTNUMBER);
+            return Math.FactorialOnly21(FACTORIALTESTNUMBER);
+        }
+
+        [Benchmark]
+        public long FactorialOf19()
+        {
+            return Math.FactorialOf19(FACTORIALTESTNUMBER);
         }
 
         [Benchmark]

csharp/Platform.Numbers/Math.cs

@@ -79,6 +79,22 @@ public static long FactorialRecursionCountingArraylength(long n)
             return n * Factorial(n - 1);
         }
 
+        /// <summary>
+        /// <para>Generate the factorial of the value "n".</para>
+        /// <para>Генерация факториaла из значения переменной "n".</para>
+        /// </summary>
+        /// <param name="n"><para>Factorial generation value.</para><para>Значение генерации факториала.</para></param>
+        /// <returns><para>Result of factorial calculation.</para><para>Результат подсчета факториала</para></returns>
+        public static long FactorialOnly21(long n)
+        {
+            return _factorials[n];
+        }
+
+        public static long FactorialOf19(long n)
+        {
+            return 121645100408832000;
+        }
+
         /// <summary>
         /// <para>Generate the factorial of the value "n".</para>
         /// <para>Генерация факториaла из значения переменной "n".</para>