Added the Fibonacci Solution with Dynamic programmng

src/InterviewQuestions/Program.cs

@@ -14,7 +14,25 @@ static void Main(string[] args)
 
             var array = ArrayViewModel.LeftRotationByD(new int[] { 1, 2, 3, 4, 5 }, 1);
             LinkedList<int> linkedlist = new LinkedList<int>(new int[] { 1, 2, 3, 4, 5 });
-            var fib = RecursionViewModel.Fibonacci(3);
+
+            var fibN1 = 40;
+            var watch = System.Diagnostics.Stopwatch.StartNew();
+            var fib = RecursionViewModel.Fibonacci(fibN1);
+            watch.Stop();
+            var elapsedMs = watch.ElapsedMilliseconds;
+            Console.WriteLine(string.Format("Fib Recursion n = {0} solution {2} Elapsed Ms {1}", fibN1, elapsedMs, fib));
+
+
+            Console.WriteLine(string.Format("Fib DP n = {0} solution {1}", fibN1, RecursionViewModel.Fibonacci_DynamicProgramming(fibN1)));
+
+            var fibN2 = 40000;
+            var watch2 = System.Diagnostics.Stopwatch.StartNew();
+            var fib2 = RecursionViewModel.Fibonacci_DynamicProgramming(fibN2);
+            watch2.Stop();
+            var elapsedMs2 = watch2.ElapsedMilliseconds;
+            Console.WriteLine(string.Format("Fib DP n = {0} solution {2}  Elapsed Ms {1}", fibN2, elapsedMs2, fib2));
+
+
             var palindrome = StringViewModel.IsStringPalindrome("Savvas");
             var sorted = LinkedListViewModel.InsertItemInSortedList(linkedlist, new LinkedListNode<int>(1));
             var removed = LinkedListViewModel.RemoveDuplicatesFromSortedList(linkedlist);

src/InterviewQuestions/ViewModels/RecursionViewModel.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Numerics;
 using System.Text;
 
 namespace InterviewQuestions.ViewModels
@@ -17,5 +18,19 @@ public static int Fibonacci(int n)
             }
         }
 
+        public static BigInteger Fibonacci_DynamicProgramming(int n)
+        {
+            var F = new BigInteger[n + 1];
+            F[0] = 0;
+            F[1] = 1;
+
+            for (int i = 2; i < F.Length; i++)
+            {
+                F[i] = F[i - 1] + F[i - 2];
+            }
+
+            return F[n];
+        }
+
     }
 }