Earth - Anya

Gemfile.lock

@@ -0,0 +1,36 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    ansi (1.5.0)
+    builder (3.2.4)
+    coderay (1.1.3)
+    method_source (1.0.0)
+    minitest (5.14.2)
+    minitest-reporters (1.4.2)
+      ansi
+      builder
+      minitest (>= 5.0)
+      ruby-progressbar
+    minitest-skip (0.0.3)
+      minitest (~> 5.0)
+    minitest-spec (0.0.2.1)
+      minitest (>= 3.0)
+    pry (0.13.1)
+      coderay (~> 1.1)
+      method_source (~> 1.0)
+    rake (13.0.1)
+    ruby-progressbar (1.10.1)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  minitest
+  minitest-reporters
+  minitest-skip
+  minitest-spec
+  pry
+  rake
+
+BUNDLED WITH
+   2.1.4

lib/recursive-methods.rb

@@ -1,49 +1,74 @@
 # 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^2)
 def factorial(n)
-    raise NotImplementedError, "Method not implemented"
+  return raise ArgumentError if n < 0
+  return 1 if n == 0 || n == 1
+  return n * factorial(n-1)
 end
 
-# Time complexity: ?
-# Space complexity: ?
+# Time complexity: O(n)
+# Space complexity: O(n^2)
 def reverse(s)
-    raise NotImplementedError, "Method not implemented"
+  return s if s.length <= 1
+  reverse_s = reverse(s[1..-1])
+  reverse_s += s[0]
+  return reverse_s
 end
 
-# Time complexity: ?
-# Space complexity: ?
+# Time complexity: O(n)
+# Space complexity: O(n^2)
 def reverse_inplace(s)
-    raise NotImplementedError, "Method not implemented"
+  return s if s.length <= 1
+  n = s[-1] + reverse_inplace(s[1..-2]) + s[0]
+  s.replace n # I don't know how to reverse in place without using .replace...
 end
 
-# Time complexity: ?
-# Space complexity: ?
+# Time complexity: O(n)
+# Space complexity: O(n)
 def bunny(n)
-    raise NotImplementedError, "Method not implemented"
+  return n if n == 0
+  return 2 + bunny(n-1)
 end
 
-# Time complexity: ?
-# Space complexity: ?
+# Time complexity: O(n)
+# Space complexity: O(n^2)
 def nested(s)
-    raise NotImplementedError, "Method not implemented"
+  return true if s.length == 0
+  return false unless s[0] == "(" && s[-1] == ")"
+  return nested(s[1..-2])
 end
 
-# Time complexity: ?
-# Space complexity: ?
+# Time complexity: O(n)
+# Space complexity: O(n^2)
 def search(array, value)
-    raise NotImplementedError, "Method not implemented"
+  return false if array == []
+  return true if array[0] == value
+  return search(array[1..-1], value)
 end
 
-# Time complexity: ?
-# Space complexity: ?
+# Time complexity: O(n)
+# Space complexity: O(n^2)
 def is_palindrome(s)
-    raise NotImplementedError, "Method not implemented"
+  return true if s == ""
+  return false unless s[0] == s[-1]
+  return is_palindrome(s[1..-2])
+end
+
+# Time complexity: O(n)
+# Space complexity: O(n^2)
+def helper_digit_match(n_string, m_string, matches)
+  return matches if n_string[-1].nil? || n_string[-1].nil?
+  if n_string[-1] == m_string[-1]
+    helper_digit_match(n_string[0..-2], m_string[0..-2], matches += 1)
+  else
+    helper_digit_match(n_string[0..-2], m_string[0..-2], matches)
+  end
 end
 
-# Time complexity: ?
-# Space complexity: ?
 def digit_match(n, m)
-    raise NotImplementedError, "Method not implemented"
+  n_string = n.to_s
+  m_string = m.to_s
+  return helper_digit_match(n_string, m_string, 0)
 end

test/recursion_writing_test.rb

@@ -167,7 +167,7 @@
   end
 end
 
-xdescribe "nested" do
+describe "nested" do
   it "will return true for empystring" do
     # Arrange
     string = ""
@@ -213,7 +213,7 @@
   end
 end
 
-xdescribe "search" do
+describe "search" do
   it "will return false for empty array" do
     # Arrange
     item = "a"
@@ -227,43 +227,43 @@
   end
 
   it "will return true when looking for something in the array" do
-  # Arrange
-  item = "a"
-  array = ["b", "c", "a"]
+    # Arrange
+    item = "a"
+    array = ["b", "c", "a"]
 
-  # Act
-  answer = search(array, item)
+    # Act
+    answer = search(array, item)
 
-  # Assert
-  expect(answer).must_equal true
+    # Assert
+    expect(answer).must_equal true
   end
 
   it "will return false when looking for something not in the array" do
     # Arrange
     item = "x"
     array = ["b", "c", "a"]
-  
+
     # Act
     answer = search(array, item)
-  
+
     # Assert
     expect(answer).must_equal false
-    end
-
-    it "will return true when finding something at the front of the array" do
-      # Arrange
-      item = "b"
-      array = ["b", "c", "a"]
-    
-      # Act
-      answer = search(array, item)
-    
-      # Assert
-      expect(answer).must_equal true
-    end      
+  end
+
+  it "will return true when finding something at the front of the array" do
+    # Arrange
+    item = "b"
+    array = ["b", "c", "a"]
+
+    # Act
+    answer = search(array, item)
+
+    # Assert
+    expect(answer).must_equal true
+  end
 end
 
-xdescribe "is_palindrome" do
+describe "is_palindrome" do
   it "will return true for emptystring" do
     # Arrange
     string = ""
@@ -298,7 +298,7 @@
   end
 end
 
-xdescribe "digit_match" do
+describe "digit_match" do
   it "returns 4 for 1072503891 and 62530841" do
     # Arrange
     num1 = 1072503891
@@ -334,7 +334,7 @@
     # Assert
     expect(answer).must_equal 3
   end
-  
+
   it "returns 1 for (0, 0)" do
     # Arrange
     num1 = 0
@@ -346,7 +346,7 @@
     # Assert
     expect(answer).must_equal 1
   end
-  
+
   it "returns 1 for (10, 20)" do
     # Arrange
     num1 = 10
@@ -359,3 +359,46 @@
     expect(answer).must_equal 1
   end
 end
+
+
+
+# Sam's reverse in line tests
+
+describe "reverse_in_place" do
+  it "will reverse 'cat'" do
+    # Arrange
+    string = "cat"
+    # Act
+    answer = reverse_inplace(string)
+    # Assert
+    expect(answer).must_equal "tac"
+    expect(string).must_equal(answer)
+  end
+  it "will reverse 'a'" do
+    # Arrange
+    string = "a"
+    # Act
+    answer = reverse_inplace(string)
+    # Assert
+    expect(answer).must_equal "a"
+    expect(string).must_equal(answer)
+  end
+  it "will reverse empty string " do
+    # Arrange
+    string = ""
+    # Act
+    answer = reverse_inplace(string)
+    # Assert
+    expect(answer).must_equal ""
+    expect(string).must_equal(answer)
+  end
+  it "will reverse 'apple'" do
+    # Arrange
+    string = "apple"
+    # Act
+    answer = reverse_inplace(string)
+    # Assert
+    expect(answer).must_equal "elppa"
+    expect(string).must_equal(answer)
+  end
+end