Fire: Ayesha Recursion writing methods

.floo

@@ -0,0 +1,3 @@
+{
+    "url": "https://floobits.com/ayesha/recursion-writing"
+}

.flooignore

@@ -0,0 +1,6 @@
+extern
+node_modules
+tmp
+vendor
+.idea/workspace.xml
+.idea/misc.xml

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 +1,124 @@
+# frozen_string_literal: true
+
 # 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"
+  if n.negative?
+    raise ArgumentError, 'n must be greater than or equal to 0.'
+  elsif n.zero?
+    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"
+  if s.length == 0 || s.length == 1
+    return s
+  end
+    return s[s.length-1] + reverse(s[0, s.length - 1])
 end
 
-# Time complexity: ?
-# Space complexity: ?
+# Time complexity: O(n^2)
+# Space complexity: O(n^2)
 def reverse_inplace(s)
-    raise NotImplementedError, "Method not implemented"
+
+  if s.length.zero? || s.length == 1
+    return s
+  end
+  length = s.length - 1
+  return pointers(s, 0, length)
+
+end
+
+def pointers(s, start_point, end_point)
+  if start_point >= end_point
+    return s
+  end
+  temp = s[start_point]
+  s[start_point] = s[end_point]
+  s[end_point] = temp
+  return pointers(s, (start_point + 1), (end_point - 1))
 end
 
-# Time complexity: ?
-# Space complexity: ?
+# Time complexity: O(n)
+# Space complexity: O(n)
 def bunny(n)
-    raise NotImplementedError, "Method not implemented"
+  if n.negative?
+    raise ArgumentError, 'n must be greater than or equal to 0.'
+  elsif n.zero?
+    0
+  else
+    bunny(n - 1) + 2
+  end
 end
 
-# Time complexity: ?
-# Space complexity: ?
+# Time complexity: O(n)
+# Space complexity: O(n)
 def nested(s)
-    raise NotImplementedError, "Method not implemented"
+  right_parenthesis = ')'
+  left_parenthesis = '('
+  if s.nil? || s.length.zero?
+    true
+  elsif s.length > 1
+    if s[0] == left_parenthesis && s[-1] == right_parenthesis
+      nested(s[1...-1])
+    else
+      false
+    end
+  else
+    false
+  end
 end
 
-# Time complexity: ?
-# Space complexity: ?
+# Time complexity: O(n)
+# Space complexity: O(n)
 def search(array, value)
-    raise NotImplementedError, "Method not implemented"
+  if array.nil? || array.length.zero?
+    return false
+  elsif array[0] == value
+    return true
+  else
+    search(array[1..-1], value)
+  end
 end
 
-# Time complexity: ?
-# Space complexity: ?
+# Time complexity: O(n)
+# Space complexity: O(n)
 def is_palindrome(s)
-    raise NotImplementedError, "Method not implemented"
+  s = s.gsub(/[^[:alnum:]]/, '').downcase
+  if s.nil? || s.length.zero?
+    true
+  else
+    if s[0] == s[-1]
+      return is_palindrome(s[1...-1])
+    else
+      return false
+    end
+    false
+  end
 end
 
-# Time complexity: ?
-# Space complexity: ?
-def digit_match(n, m)
-    raise NotImplementedError, "Method not implemented"
-end
+# Time complexity: O(n^2)
+# Space complexity: O(n^2)
+def digit_match(n, m);
+  if n.nil? || m.nil?
+    return 0
+  elsif n.to_s.empty? || m.to_s.empty?
+    return 0
+  elsif n.to_s[-1] == m.to_s[-1]
+    return 1 + digit_match(n.to_s[0..-2], m.to_s[0..-2])
+  else
+    return 0 + digit_match(n.to_s[0..-2], m.to_s[0..-2])
+  end
+end
+
+# Time complexity: O(n^2)
+# Space complexity: O(n^2)
+
+
+

recursion-writing.iml

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+<?xml version="1.0" encoding="UTF-8"?>
+<module type="RUBY_MODULE" version="4">
+  <component name="NewModuleRootManager">
+    <content url="file://$MODULE_DIR$" />
+    <orderEntry type="jdk" jdkName="rbenv: 2.6.5" jdkType="RUBY_SDK" />
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" scope="PROVIDED" name="ansi (v1.5.0, rbenv: 2.6.5) [gem]" level="application" />
+    <orderEntry type="library" scope="PROVIDED" name="builder (v3.2.4, rbenv: 2.6.5) [gem]" level="application" />
+    <orderEntry type="library" scope="PROVIDED" name="bundler (v2.1.4, rbenv: 2.6.5) [gem]" level="application" />
+    <orderEntry type="library" scope="PROVIDED" name="coderay (v1.1.3, rbenv: 2.6.5) [gem]" level="application" />
+    <orderEntry type="library" scope="PROVIDED" name="method_source (v1.0.0, rbenv: 2.6.5) [gem]" level="application" />
+    <orderEntry type="library" scope="PROVIDED" name="minitest (v5.14.2, rbenv: 2.6.5) [gem]" level="application" />
+    <orderEntry type="library" scope="PROVIDED" name="minitest-reporters (v1.4.2, rbenv: 2.6.5) [gem]" level="application" />
+    <orderEntry type="library" scope="PROVIDED" name="minitest-skip (v0.0.3, rbenv: 2.6.5) [gem]" level="application" />
+    <orderEntry type="library" scope="PROVIDED" name="minitest-spec (v0.0.2.1, rbenv: 2.6.5) [gem]" level="application" />
+    <orderEntry type="library" scope="PROVIDED" name="pry (v0.13.1, rbenv: 2.6.5) [gem]" level="application" />
+    <orderEntry type="library" scope="PROVIDED" name="rake (v13.0.1, rbenv: 2.6.5) [gem]" level="application" />
+    <orderEntry type="library" scope="PROVIDED" name="ruby-progressbar (v1.10.1, rbenv: 2.6.5) [gem]" level="application" />
+  </component>
+  <component name="RubyModuleProperties">
+    <option name="autoCreated" value="true" />
+  </component>
+</module>

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"
@@ -263,7 +263,7 @@
     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