From 6150d996ad2496cda7e210e7b533835b77a22553 Mon Sep 17 00:00:00 2001
From: Mariya Burrows <mariya.burrows@gmail.com>
Date: Wed, 13 Nov 2019 20:57:27 -0800
Subject: [PATCH] added some recursion methods

---
 lib/recursive-methods.rb       |  33 +++-
 test/recursion_writing_test.rb | 336 ++++++++++++++++-----------------
 2 files changed, 192 insertions(+), 177 deletions(-)

diff --git a/lib/recursive-methods.rb b/lib/recursive-methods.rb
index fbf6faa..a3c28e6 100644
--- a/lib/recursive-methods.rb
+++ b/lib/recursive-methods.rb
@@ -3,47 +3,62 @@
 # Time complexity: ?
 # Space complexity: ?
 def factorial(n)
-    raise NotImplementedError, "Method not implemented"
+  if n < 0
+    raise ArgumentError
+  elsif (n == 1) || (n== 0)
+    return 1
+  else
+    return n * factorial(n - 1)
+  end
 end
 
 # Time complexity: ?
 # Space complexity: ?
-def reverse(s)
-    raise NotImplementedError, "Method not implemented"
+def reverse(s) 
+  if s.length == 0
+    return s 
+  end
+  a = s[0]
+  b = s.slice(1, s.length - 1)
+  return reverse(b) + a 
 end
 
 # Time complexity: ?
 # Space complexity: ?
 def reverse_inplace(s)
-    raise NotImplementedError, "Method not implemented"
+  raise NotImplementedError, "Method not implemented"
 end
 
 # Time complexity: ?
 # Space complexity: ?
 def bunny(n)
-    raise NotImplementedError, "Method not implemented"
+  if n == 0
+    return n
+  end
+  
+  return bunny(n - 1) + 2  
 end
 
 # Time complexity: ?
 # Space complexity: ?
 def nested(s)
-    raise NotImplementedError, "Method not implemented"
+  
 end
 
 # Time complexity: ?
 # Space complexity: ?
 def search(array, value)
-    raise NotImplementedError, "Method not implemented"
+  raise NotImplementedError, "Method not implemented"
 end
 
 # Time complexity: ?
 # Space complexity: ?
 def is_palindrome(s)
-    raise NotImplementedError, "Method not implemented"
+  raise NotImplementedError, "Method not implemented"
 end
 
 # Time complexity: ?
 # Space complexity: ?
 def digit_match(n, m)
-    raise NotImplementedError, "Method not implemented"
+  raise NotImplementedError, "Method not implemented"
 end
\ No newline at end of file
diff --git a/test/recursion_writing_test.rb b/test/recursion_writing_test.rb
index 820810e..f8f781c 100644
--- a/test/recursion_writing_test.rb
+++ b/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"
@@ -84,52 +84,52 @@
 end
 
 
-xdescribe "reverse_in_place" do
-  it "will reverse 'cat'" do
-    # Arrange
-    string = "cat"
+# xdescribe "reverse_in_place" do
+#   it "will reverse 'cat'" do
+#     # Arrange
+#     string = "cat"
 
-    # Act
-    answer = reverse_inplace(string)
+#     # Act
+#     answer = reverse_inplace(string)
 
-    # Assert
-    expect(answer).must_equal "tac"
-  end
+#     # Assert
+#     expect(answer).must_equal "tac"
+#   end
 
-  it "will reverse 'a'" do
-    # Arrange
-    string = "a"
+#   it "will reverse 'a'" do
+#     # Arrange
+#     string = "a"
 
-    # Act
-    answer = reverse_inplace(string)
+#     # Act
+#     answer = reverse_inplace(string)
 
-    # Assert
-    expect(answer).must_equal "a"
-  end
+#     # Assert
+#     expect(answer).must_equal "a"
+#   end
 
-  it "will reverse empty string " do
-    # Arrange
-    string = ""
+#   it "will reverse empty string " do
+#     # Arrange
+#     string = ""
 
-    # Act
-    answer = reverse_inplace(string)
+#     # Act
+#     answer = reverse_inplace(string)
 
-    # Assert
-    expect(answer).must_equal ""
-  end
-  it "will reverse 'apple'" do
-    # Arrange
-    string = "apple"
+#     # Assert
+#     expect(answer).must_equal ""
+#   end
+#   it "will reverse 'apple'" do
+#     # Arrange
+#     string = "apple"
 
-    # Act
-    answer = reverse_inplace(string)
+#     # Act
+#     answer = reverse_inplace(string)
 
-    # Assert
-    expect(answer).must_equal "elppa"
-  end
-end
+#     # Assert
+#     expect(answer).must_equal "elppa"
+#   end
+# end
 
-xdescribe "bunny" do
+describe "bunny" do
   it "returns 0 for 0 bunnies" do
     # Arrange
     count = 0
@@ -210,149 +210,149 @@
   end
 end
 
-xdescribe "search" do
-  it "will return false for empty array" do
-    # Arrange
-    item = "a"
-    array = []
+# xdescribe "search" do
+#   it "will return false for empty array" do
+#     # Arrange
+#     item = "a"
+#     array = []
 
-    # Act
-    answer = search(array, item)
+#     # Act
+#     answer = search(array, item)
 
-    # Assert
-    expect(answer).must_equal false
-  end
+#     # Assert
+#     expect(answer).must_equal false
+#   end
 
-  it "will return true when looking for something in the array" do
-  # Arrange
-  item = "a"
-  array = ["b", "c", "a"]
+#   it "will return true when looking for something in the array" do
+#   # Arrange
+#   item = "a"
+#   array = ["b", "c", "a"]
 
-  # Act
-  answer = search(array, item)
+#   # Act
+#   answer = search(array, item)
 
-  # Assert
-  expect(answer).must_equal true
-  end
+#   # 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"]
+#   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)
+#     # 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"]
+#     # 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)
+#       # Act
+#       answer = search(array, item)
     
-      # Assert
-      expect(answer).must_equal true
-    end      
-end
-
-xdescribe "is_palindrome" do
-  it "will return true for emptystring" do
-    # Arrange
-    string = ""
-
-    # Act
-    answer = is_palindrome(string)
-
-    # Assert
-    expect(answer).must_equal true
-  end
-
-  it "will return true for a palindrome" do
-    # Arrange
-    string = "racecar"
-
-    # Act
-    answer = is_palindrome(string)
-
-    # Assert
-    expect(answer).must_equal true
-  end
-
-  it "will return false for a nonpalindrome" do
-    # Arrange
-    string = "raecar"
-
-    # Act
-    answer = is_palindrome(string)
-
-    # Assert
-    expect(answer).must_equal false
-  end
-end
-
-xdescribe "digit_match" do
-  it "returns 4 for 1072503891 and 62530841" do
-    # Arrange
-    num1 = 1072503891
-    num2 = 62530841
-
-    # Act
-    answer = digit_match(num1, num2)
-
-     # Assert
-     expect(answer).must_equal 4
-  end
-
-  it "returns 0 for nonmatching numbers" do
-    # Arrange
-    num1 = 0
-    num2 = 62530841
-
-    # Act
-    answer = digit_match(num1, num2)
-
-     # Assert
-     expect(answer).must_equal 0
-  end
-
-  it "returns 3 for 841 and 62530841" do
-    # Arrange
-    num1 = 841
-    num2 = 62530841
-
-    # Act
-    answer = digit_match(num1, num2)
-
-     # Assert
-     expect(answer).must_equal 3
-  end
+#       # Assert
+#       expect(answer).must_equal true
+#     end      
+# end
+
+# xdescribe "is_palindrome" do
+#   it "will return true for emptystring" do
+#     # Arrange
+#     string = ""
+
+#     # Act
+#     answer = is_palindrome(string)
+
+#     # Assert
+#     expect(answer).must_equal true
+#   end
+
+#   it "will return true for a palindrome" do
+#     # Arrange
+#     string = "racecar"
+
+#     # Act
+#     answer = is_palindrome(string)
+
+#     # Assert
+#     expect(answer).must_equal true
+#   end
+
+#   it "will return false for a nonpalindrome" do
+#     # Arrange
+#     string = "raecar"
+
+#     # Act
+#     answer = is_palindrome(string)
+
+#     # Assert
+#     expect(answer).must_equal false
+#   end
+# end
+
+# xdescribe "digit_match" do
+#   it "returns 4 for 1072503891 and 62530841" do
+#     # Arrange
+#     num1 = 1072503891
+#     num2 = 62530841
+
+#     # Act
+#     answer = digit_match(num1, num2)
+
+#      # Assert
+#      expect(answer).must_equal 4
+#   end
+
+#   it "returns 0 for nonmatching numbers" do
+#     # Arrange
+#     num1 = 0
+#     num2 = 62530841
+
+#     # Act
+#     answer = digit_match(num1, num2)
+
+#      # Assert
+#      expect(answer).must_equal 0
+#   end
+
+#   it "returns 3 for 841 and 62530841" do
+#     # Arrange
+#     num1 = 841
+#     num2 = 62530841
+
+#     # Act
+#     answer = digit_match(num1, num2)
+
+#      # Assert
+#      expect(answer).must_equal 3
+#   end
   
-  it "returns 1 for (0, 0)" do
-    # Arrange
-    num1 = 0
-    num2 = 0
+#   it "returns 1 for (0, 0)" do
+#     # Arrange
+#     num1 = 0
+#     num2 = 0
 
-    # Act
-    answer = digit_match(num1, num2)
+#     # Act
+#     answer = digit_match(num1, num2)
 
-     # Assert
-     expect(answer).must_equal 1
-  end
+#      # Assert
+#      expect(answer).must_equal 1
+#   end
   
-  it "returns 1 for (10, 20)" do
-    # Arrange
-    num1 = 10
-    num2 = 20
-
-    # Act
-    answer = digit_match(num1, num2)
-
-     # Assert
-     expect(answer).must_equal 1
-  end
-end
+#   it "returns 1 for (10, 20)" do
+#     # Arrange
+#     num1 = 10
+#     num2 = 20
+
+#     # Act
+#     answer = digit_match(num1, num2)
+
+#      # Assert
+#      expect(answer).must_equal 1
+#   end
+#end