Leaves - Mariya Burrows

lib/fibonacci.rb

@@ -1,8 +1,30 @@
 # Improved Fibonacci
 
-# Time Complexity - ?
-# Space Complexity - ?  (should be O(n))
+# Time Complexity - ?  O(n)
+# Space Complexity - ?  O(n)
 # Hint, you may want a recursive helper method
 def fibonacci(n)
-
+  return fib_helper({}, n)
+
 end
+
+
+def fib_helper(solutions, n)
+  if solutions.include?(n)
+    return solutions[n]
+  end
+
+  if n == 0
+    solutions[n] = 0
+    return 0 
+  elsif n == 1
+    solutions[n] = 1
+    return 1 
+  elsif n >= 2
+    solutions[n] = (fib_helper(solutions, n-2) + fib_helper(solutions, n-1))
+    return solutions[n]
+  else
+    raise ArgumentError
+  end
+
+end

lib/super_digit.rb

@@ -1,11 +1,32 @@
 # Superdigit
 
-# Time Complexity - ?
-# Space Complexity - ?
+# Time Complexity - O(n)
+# Space Complexity - O(n)
 def super_digit(n)
+  super_digit_helper({}, n)
 
 end
-
+
+def super_digit_helper(solutions, n)
+  if solutions[n]
+    return solutions[n]
+  end
+
+  if n.to_s.length == 1
+    solutions[n] = n
+    return solutions[n]  
+  end
+
+  string_num = n.to_s 
+
+  sum = 0
+  string_num.length.times do |i|
+    sum += (string_num[i].to_i)
+  end
+
+  solutions[n] = super_digit_helper(solutions, sum)
+  return solutions[n]
+end
 
 # Time Complexity - ?
 # Space Complexity - ?

test/super_digit_test.rb

@@ -1,6 +1,6 @@
 require_relative "test_helper"
 
-xdescribe "super_digit" do
+describe "super_digit" do
   it "will return 2 for super_digit(9875)" do
     # Act
     answer = super_digit(9875)
@@ -33,7 +33,7 @@
     expect(answer).must_equal 6
   end
 
-  describe "refined superdigit" do 
+  xdescribe "refined superdigit" do 
     it "will return 1 for n = 1 and k = 1" do
       # Act
       answer = refined_super_digit(1, 1)