Yasmin- Leaves

lib/recursive-methods.rb

@@ -1,41 +1,76 @@
 # Authoring recursive algorithms. Add comments including time and space complexity for each method.
 
-# Time complexity: ?
-# Space complexity: ?
+# Time complexity: o(n)
+# Space complexity: o(n)
 def factorial(n)
-    raise NotImplementedError, "Method not implemented"
+    # raise NotImplementedError, "Method not implemented"
+  if n < 0
+    raise ArgumentError
+  elsif n <= 1
+    return  1
+  else 
+    n * factorial(n-1)
+  end 
 end
 
-# Time complexity: ?
-# Space complexity: ?
+# Time complexity: o(n^2)
+# Space complexity: o(n^2)
 def reverse(s)
-    raise NotImplementedError, "Method not implemented"
+    # raise NotImplementedError, "Method not implemented"
+  if s.length <= 1
+    return s
+  else 
+    return s[-1] + reverse(s[0..-2]) 
+  end
 end
 
-# Time complexity: ?
-# Space complexity: ?
+# Time complexity: 
+# Space complexity: 
 def reverse_inplace(s)
     raise NotImplementedError, "Method not implemented"
+
 end
 
-# Time complexity: ?
-# Space complexity: ?
+
+# Time complexity: o(n)
+# Space complexity: o(n)
 def bunny(n)
-    raise NotImplementedError, "Method not implemented"
+    # raise NotImplementedError, "Method not implemented"
+  if n == 0
+    return 0
+  else
+    return 2 + bunny(n-1)
+  end
 end
 
-# Time complexity: ?
-# Space complexity: ?
+
+# Time complexity: o(n)
+# Space complexity: o(n^2)
 def nested(s)
-    raise NotImplementedError, "Method not implemented"
+    # raise NotImplementedError, "Method not implemented"
+  if s == ""
+    return true
+  elsif s[0] == "(" && s[-1] == ")" && nested(s[1...-1])
+     return true
+  else 
+    return false
+  end
 end
 
 # Time complexity: ?
 # Space complexity: ?
 def search(array, value)
-    raise NotImplementedError, "Method not implemented"
+    # raise NotImplementedError, "Method not implemented"
+  if array.length == 0
+    return false
+  elsif value == array[0]
+    return true
+  else 
+    return search(array[1..-1], value)
+  end
 end
 
+
 # Time complexity: ?
 # Space complexity: ?
 def is_palindrome(s)

test/recursion_writing_test.rb

@@ -38,7 +38,7 @@
   end
 end
 
-xdescribe "reverse" do
+describe "reverse" do
   it "will reverse 'cat'" do
     # Arrange
     string = "cat"
@@ -129,7 +129,7 @@
   end
 end
 
-xdescribe "bunny" do
+describe "bunny" do
   it "returns 0 for 0 bunnies" do
     # Arrange
     count = 0
@@ -164,7 +164,7 @@
   end
 end
 
-xdescribe "nested" do
+describe "nested" do
   it "will return true for empystring" do
     # Arrange
     string = ""
@@ -210,7 +210,7 @@
   end
 end
 
-xdescribe "search" do
+describe "search" do
   it "will return false for empty array" do
     # Arrange
     item = "a"