diff --git a/lib/fibonacci.rb b/lib/fibonacci.rb
index 7465c25..fddd8b6 100644
--- a/lib/fibonacci.rb
+++ b/lib/fibonacci.rb
@@ -1,8 +1,20 @@
 # Improved Fibonacci
 
-# Time Complexity - ?
-# Space Complexity - ?  (should be O(n))
+# Time Complexity - O(n)
+# Space Complexity - O(n)  (should be O(n))
 # Hint, you may want a recursive helper method
 def fibonacci(n)
- 
+  return fib_helper([0, 1], 2, n)
+end
+
+def fib_helper(solutions, current, n)
+  raise ArgumentError if n < 0
+  return n if n == 0 || n == 1
+  if current == n
+    return solutions[0] + solutions[1]
+  end
+  temp = solutions[0] + solutions[1]
+  solutions[0] = solutions[1]
+  solutions[1] = temp
+  return fib_helper(solutions, current + 1, n)
 end
diff --git a/lib/super_digit.rb b/lib/super_digit.rb
index 33e367f..0996767 100644
--- a/lib/super_digit.rb
+++ b/lib/super_digit.rb
@@ -1,15 +1,19 @@
 # Superdigit
 
-# Time Complexity - ?
-# Space Complexity - ?
+# Time Complexity - O(n^2)
+# Space Complexity - O(n)
 def super_digit(n)
-   
+  return n if n < 10
+  super_digit(n.digits.sum)
 end
-  
 
-# Time Complexity - ?
-# Space Complexity - ?
+
 def refined_super_digit(n, k)
-    
+  n = n.digits.sum * k
+  return refined_helper(n)
 end
-    
\ No newline at end of file
+
+def refined_helper(n)
+  return n if n < 10
+  super_digit(n.digits.sum)
+end
\ No newline at end of file