diff --git a/lib/linked_list.rb b/lib/linked_list.rb
index 501c60fb..d44ae309 100644
--- a/lib/linked_list.rb
+++ b/lib/linked_list.rb
@@ -12,152 +12,309 @@ def initialize(value, next_node = nil)
 
 # Defines the singly linked list
 class LinkedList
-    def initialize
-      @head = nil # keep the head private. Not accessible outside this class
-    end
+  def initialize
+    @head = nil # keep the head private. Not accessible outside this class
+  end
+
+  # method to add a new node with the specific data value in the linked list
+  # insert the new node at the beginning of the linked list
+  # Time Complexity: O(1)
+  # Space Complexity: O(1)
+  def add_first(value)
+    new_node = Node.new(value, @head)
+    @head = new_node
+  end
 
-    # method to add a new node with the specific data value in the linked list
-    # insert the new node at the beginning of the linked list
-    # Time Complexity:  
-    # Space Complexity
-    def add_first(value)
-      raise NotImplementedError
+  # method to find if the linked list contains a node with specified value
+  # returns true if found, false otherwise
+  # Time Complexity: O(n)
+  # Space Complexity: O(1)
+  def search(value)
+    current = @head
+
+    until current.next == nil
+      return true if value == current.data
+
+      current = current.next
     end
 
-    # method to find if the linked list contains a node with specified value
-    # returns true if found, false otherwise
-    # Time Complexity:  
-    # Space Complexity
-    def search(value)
-      raise NotImplementedError
+    return false
+  end
+
+  # method to return the max value in the linked list
+  # returns the data value and not the node
+  # Time Complexity: O(n)
+  # Space Complexity: O(1)
+  def find_max
+    return nil if !@head
+
+    current = @head.next
+    max_value = @head.data
+
+    until !current
+      max_value = current.data if current.data > max_value
+      current = current.next
     end
 
-    # method to return the max value in the linked list
-    # returns the data value and not the node
-    # Time Complexity:  
-    # Space Complexity
-    def find_max
-      raise NotImplementedError
+    return max_value
+  end
+
+  # method to return the min value in the linked list
+  # returns the data value and not the node
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)
+  def find_min
+    return nil if !@head
+
+    current = @head.next
+    min_value = @head.data
+
+    until !current
+      min_value = current.data if current.data < min_value
+      current = current.next
     end
 
-    # method to return the min value in the linked list
-    # returns the data value and not the node
-    # Time Complexity:  
-    # Space Complexity
-    def find_min
-      raise NotImplementedError
+    return min_value
+  end
+
+  # method that returns the length of the singly linked list
+  # Time Complexity: O(n)
+  # Space Complexity: O(1)
+  def length
+    return 0 if !@head
+
+    count = 1
+    current = @head.next
+
+    until !current
+      count += 1
+      current = current.next
     end
 
+    return count
+  end
 
-    # method that returns the length of the singly linked list
-    # Time Complexity:  
-    # Space Complexity
-    def length
-      raise NotImplementedError
+  # method that returns the value at a given index in the linked list
+  # index count starts at 0
+  # returns nil if there are fewer nodes in the linked list than the index value
+  # Time Complexity: O(n)
+  # Space Complexity: O(1)
+  def get_at_index(index)
+    count = 0
+    current = @head
+    while current != nil
+      if count == index
+        return current.data
+      end
+      current = current.next
+      count += 1
     end
+    return nil
+  end
+
+  # method to print all the values in the linked list
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)
+  def visit
+    return if @head == nil
 
-    # method that returns the value at a given index in the linked list
-    # index count starts at 0
-    # returns nil if there are fewer nodes in the linked list than the index value
-    # Time Complexity:  
-    # Space Complexity
-    def get_at_index(index)
-      raise NotImplementedError
+    current = @head
+
+    until current.next == nil
+      current = current.next
     end
+  end
 
-    # method to print all the values in the linked list
-    # Time Complexity:  
-    # Space Complexity
-    def visit
-      raise NotImplementedError
+  # method to delete the first node found with specified value
+  # Time Complexity: O(n)
+  # Space Complexity: O(1)
+  def delete(value)
+    return if !@head
+
+    if @head.data == value
+      @head = @head.next
+      return
     end
 
-    # method to delete the first node found with specified value
-    # Time Complexity:  
-    # Space Complexity
-    def delete(value)
-      raise NotImplementedError
+    previous = @head
+    current = @head.next
+
+    until value == current.data || !current
+      previous = current
+      current = current.next
     end
 
-    # method to reverse the singly linked list
-    # note: the nodes should be moved and not just the values in the nodes
-    # Time Complexity:  
-    # Space Complexity
-    def reverse
-      raise NotImplementedError
+    previous.next = current.next
+  end
+
+  # method to reverse the singly linked list
+  # note: the nodes should be moved and not just the values in the nodes
+  # Time Complexity: O(n)
+  # Space Complexity: O(1)
+  def reverse
+    return nil if @head == nil
+
+    current = @head
+    next_node = nil
+    previous_node = nil
+
+    until current == nil
+      next_node = current.next
+      current.next = previous_node
+      previous_node = current
+      current = next_node
     end
 
+    @head = previous_node
+  end
+
+  ## Advanced Exercises
+  # returns the value at the middle element in the singly linked list
+  # Time Complexity: O(n)
+  # Space Complexity: O(1)
+  def find_middle_value
+    fast = @head
+    slow = @head
 
-    ## Advanced Exercises
-    # returns the value at the middle element in the singly linked list
-    # Time Complexity:  
-    # Space Complexity
-    def find_middle_value
-      raise NotImplementedError
+    while fast != nil && fast.next != nil
+      slow = slow.next
+      fast = fast.next.next
+      if fast.next == nil
+        return slow.data
+      end
     end
+  end
+
+  # find the nth node from the end and return its value
+  # assume indexing starts at 0 while counting to n
+  # Time Complexity: O(n)
+  # Space Complexity: O(1)
+  def find_nth_from_end(n)
+    return nil if @head == nil
+
+    fast = @head
+    slow = @head
+    count = 0
 
-    # find the nth node from the end and return its value
-    # assume indexing starts at 0 while counting to n
-    # Time Complexity:  
-    # Space Complexity
-    def find_nth_from_end(n)
-      raise NotImplementedError
+    until count == n
+      fast = fast.next
+      return nil if fast == nil
+      count += 1
     end
 
-    # checks if the linked list has a cycle. A cycle exists if any node in the
-    # linked list links to a node already visited.
-    # returns true if a cycle is found, false otherwise.
-    # Time Complexity:  
-    # Space Complexity
-    def has_cycle
-      raise NotImplementedError
+    until fast.next == nil
+      fast = fast.next
+      slow = slow.next
     end
 
+    return slow.data
+  end
 
-    # Additional Exercises 
-    # returns the value in the first node
-    # returns nil if the list is empty
-    # Time Complexity:  
-    # Space Complexity
-    def get_first
-      raise NotImplementedError
+  # checks if the linked list has a cycle. A cycle exists if any node in the
+  # linked list links to a node already visited.
+  # returns true if a cycle is found, false otherwise.
+  # Time Complexity: O(n)
+  # Space Complexity: O(1)
+  def has_cycle
+    slow = @head
+    fast = @head
+    while fast != nil && fast.next != nil
+      slow = slow.next
+      fast = fast.next.next
+      if slow == fast
+        return true
+      end
     end
+    return false
+  end
+
+  # Additional Exercises
+  # returns the value in the first node
+  # returns nil if the list is empty
+  # Time Complexity: O(n)
+  # Space Complexity: O(1)
+  def get_first
+    return nil if !@head
+
+    @head.data
+  end
+
+  # method that inserts a given value as a new last node in the linked list
+  # Time Complexity: O(n)
+  # Space Complexity: O(1)
+  def add_last(value)
+    return self.add_first(value) if !@head
 
-    # method that inserts a given value as a new last node in the linked list
-    # Time Complexity:  
-    # Space Complexity
-    def add_last(value)
-      raise NotImplementedError
+    new_node = Node.new(value)
+
+    current = @head
+
+    until !current.next
+      current = current.next
     end
 
-    # method that returns the value of the last node in the linked list
-    # returns nil if the linked list is empty
-    # Time Complexity:  
-    # Space Complexity
-    def get_last
-      raise NotImplementedError
+    current.next = new_node
+  end
+
+  # method that returns the value of the last node in the linked list
+  # returns nil if the linked list is empty
+  # Time Complexity: O(n)
+  # Space Complexity: O(1)
+  def get_last
+    return nil if !@head
+    return @head.data if !@head.next
+
+    current = @head.next
+
+    until !current.next
+      current = current.next
     end
 
-    # method to insert a new node with specific data value, assuming the linked
-    # list is sorted in ascending order
-    # Time Complexity:  
-    # Space Complexity
-    def insert_ascending(value)
-      raise NotImplementedError
+    return current.data
+  end
+
+  # method to insert a new node with specific data value, assuming the linked
+  # list is sorted in ascending order
+  # Time Complexity: O(n)
+  # Space Complexity: O(1)
+  def insert_ascending(value)
+    new_node = Node.new(value)
+    if @head == nil
+      @head = new_node
+      return @head.data
     end
 
-    # Helper method for tests
-    # Creates a cycle in the linked list for testing purposes
-    # Assumes the linked list has at least one node
-    def create_cycle
-      return if @head == nil # don't do anything if the linked list is empty
+    if @head.data > new_node.data
+      temp_node = @head
+      @head = new_node
+      new_node.next = temp_node
+      return @head.data
+    end
 
-      # navigate to last node
-      current = @head
-      while current.next != nil
-          current = current.next
+    curr_node = @head
+    while curr_node != nil
+      if curr_node.data <= new_node.data && curr_node.next.data > new_node.data
+        temp_node = curr_node.next
+        curr_node.next = new_node
+        new_node.next = temp_node
+        return new_node.data
       end
+      curr_node = curr_node.next
+    end
+  end
 
-      current.next = @head # make the last node link to first node
+  # Helper method for tests
+  # Creates a cycle in the linked list for testing purposes
+  # Assumes the linked list has at least one node
+  def create_cycle
+    return if @head == nil # don't do anything if the linked list is empty
+
+    # navigate to last node
+    current = @head
+    while current.next != nil
+      current = current.next
     end
+
+    current.next = @head # make the last node link to first node
+  end
 end
diff --git a/test/linked_list_test.rb b/test/linked_list_test.rb
index a7ee3769..d97e3306 100644
--- a/test/linked_list_test.rb
+++ b/test/linked_list_test.rb
@@ -1,241 +1,240 @@
-require 'minitest/autorun'
-require 'minitest/reporters'
-require 'minitest/skip_dsl'
-
-require_relative 'test_helper'
+require "minitest/autorun"
+require "minitest/reporters"
+require "minitest/skip_dsl"
 
+require_relative "test_helper"
 
 Minitest::Reporters.use! Minitest::Reporters::SpecReporter.new
 
 describe LinkedList do
-    # Arrange
-    before do
-        @list = LinkedList.new
-    end
-
-    describe 'initialize' do
-        it 'can be created' do
-
-            # Assert
-            expect(@list).must_be_kind_of LinkedList
-        end
-    end
-
-    describe 'add_first & get_first' do
-        it 'can add values to an empty list' do
-            # Act
-            @list.add_first(3)
-
-            # Assert
-            expect(@list.get_first).must_equal 3
-        end
-
-        it 'will put the last added item to the front of the list' do
-            # Act
-            @list.add_first(1)
-            @list.add_first(2)
-
-            # Assert
-            expect(@list.get_first).must_equal 2
-
-            # Act again
-            @list.add_first(3)
-
-            # Assert
-            expect(@list.get_first).must_equal 3
-        end
-
-        it 'will return `nil` for `getFirst` if the list is empty' do
-            # Act-Assert
-            expect(@list.get_first).must_be_nil
-        end
-    end
-
-    describe "length" do
-        it "will return 0 for an empty list" do
-            # Act-Assert
-            expect(@list.length).must_equal 0
-        end
-
-        it "will return the length for nonempty lists" do
-            # Arrange
-            count = 0
-            while count < 5
-                @list.add_first(count)
-                count += 1
-                # Act-Assert
-                expect(@list.length).must_equal count
-            end
-        end
-    end
-
-    describe "addLast & getLast" do
-        it "will add to the front if the list is empty" do
-            # Arrange
-            @list.add_last(1)
-            # Act-Assert
-            expect(@list.get_first).must_equal 1
-        end
-
-        it "will put new items to the rear of the list" do
-            # Arrange
-            @list.add_last(2)
-            # Act-Assert
-            expect(@list.length).must_equal 1
-            expect(@list.get_last).must_equal 2
-
-            # Arrange
-            @list.add_last(3)
-            # Act-Assert
-            expect(@list.get_first).must_equal 2
-            expect(@list.get_last).must_equal 3
-            expect(@list.length).must_equal 2
-
-            @list.add_last(4)
-            expect(@list.get_first).must_equal 2
-            expect(@list.get_last).must_equal 4
-            expect(@list.length).must_equal 3
-        end
-        
-        it "will return `nil` for `get_last` if the list is empty" do
-            # Act-Assert
-            expect(@list.get_last).must_be_nil
-        end
-    end
-
-    describe 'get_at_index' do
-        it 'returns nil if the index is outside the bounds of the list' do
-            # Act-Assert
-            expect(@list.get_at_index(3)).must_be_nil
-        end
-
-        it 'can retrieve an item at an index in the list' do
-            # Arrange
-            @list.add_first(1)
-            @list.add_first(2)
-            @list.add_first(3)
-            @list.add_first(4)
-
-            # Act-Assert
-            expect(@list.get_at_index(0)).must_equal 4
-            expect(@list.get_at_index(1)).must_equal 3
-            expect(@list.get_at_index(2)).must_equal 2
-            expect(@list.get_at_index(3)).must_equal 1
-        end
-    end
-
-    describe 'max and min values' do
-        it 'returns nil if the list is empty' do
-            # Act-Assert
-            expect(@list.find_max()).must_be_nil
-            expect(@list.find_min()).must_be_nil
-        end
-
-        it 'can retrieve the max and min values in the list' do
-            # Arrange
-            count = 0
-            while count < 5
-                @list.add_first(count)
-                expect(@list.find_max).must_equal count
-                expect(@list.find_min).must_equal 0
-                count += 1
-            end
-            @list.add_last(100)
-            @list.add_first(-12)
-            
-            # Act-Assert
-            expect(@list.find_max).must_equal 100
-            expect(@list.find_min).must_equal(-12)
-        end
-    end
-
-    describe "delete" do
-        it "delete from empty linked list is a no-op" do
-            # Assert
-            expect(@list.length).must_equal 0
-            # Act
-            @list.delete(4)
-            # Assert
-            expect(@list.length).must_equal 0
-        end
-
-        it "can delete valid values from list" do
-            # Arrange
-            @list.add_last(9)
-            @list.add_last(10)
-            @list.add_first(4)
-            @list.add_first(3)
-            @list.add_first(2)
-            
-            # Act
-            # delete fist node (requires updating head)
-            @list.delete(2)
-            
-            # Assert
-            expect(@list.get_first).must_equal 3
-            expect(@list.length).must_equal 4
-            expect(@list.get_last).must_equal 10
-            expect(@list.find_max).must_equal 10
-            expect(@list.find_min).must_equal 3
-            
-            # Act (again)
-            # delete last node
-            @list.delete(10)
-            # Assert
-            expect(@list.get_first).must_equal 3
-            expect(@list.length).must_equal 3
-            expect(@list.get_last).must_equal 9
-            expect(@list.find_max).must_equal 9
-            expect(@list.find_min).must_equal 3
-
-            # delete fist node (requires updating head)
-            @list.delete(4)
-            expect(@list.get_first).must_equal 3
-            expect(@list.length).must_equal 2
-            expect(@list.get_last).must_equal 9
-            expect(@list.find_max).must_equal 9
-            expect(@list.find_min).must_equal 3
-        end
-    end
-
-    describe "nth_from_the_end" do
-        it 'returns nil if n is outside the bounds of the list' do
-            # Act-Assert
-            expect(@list.find_nth_from_end(3)).must_be_nil
-        end
-
-        it 'can retrieve an item at index n from the end in the list' do
-            # Arrange
-            @list.add_first(1)
-            @list.add_first(2)
-            @list.add_first(3)
-            @list.add_first(4)
-
-            # Act-Assert
-            expect(@list.find_nth_from_end(0)).must_equal 1
-            expect(@list.find_nth_from_end(1)).must_equal 2
-            expect(@list.find_nth_from_end(2)).must_equal 3
-            expect(@list.find_nth_from_end(3)).must_equal 4
-            expect(@list.find_nth_from_end(4)).must_be_nil
-        end
-    end
-
-    describe "reverse" do
-        it 'can retrieve an item at index n from the end in the list' do
-            # Arrange
-            @list.add_first(4)
-            @list.add_first(3)
-            @list.add_first(2)
-            @list.add_first(1)
-            
-            # Act
-            @list.reverse
-
-            # Assert
-            expect(@list.find_nth_from_end(0)).must_equal 1
-            expect(@list.find_nth_from_end(1)).must_equal 2
-            expect(@list.find_nth_from_end(2)).must_equal 3
-            expect(@list.find_nth_from_end(3)).must_equal 4
-        end
+  # Arrange
+  before do
+    @list = LinkedList.new
+  end
+
+  describe "initialize" do
+    it "can be created" do
+
+      # Assert
+      expect(@list).must_be_kind_of LinkedList
+    end
+  end
+
+  describe "add_first & get_first" do
+    it "can add values to an empty list" do
+      # Act
+      @list.add_first(3)
+
+      # Assert
+      expect(@list.get_first).must_equal 3
+    end
+
+    it "will put the last added item to the front of the list" do
+      # Act
+      @list.add_first(1)
+      @list.add_first(2)
+
+      # Assert
+      expect(@list.get_first).must_equal 2
+
+      # Act again
+      @list.add_first(3)
+
+      # Assert
+      expect(@list.get_first).must_equal 3
+    end
+
+    it "will return `nil` for `getFirst` if the list is empty" do
+      # Act-Assert
+      expect(@list.get_first).must_be_nil
+    end
+  end
+
+  describe "length" do
+    it "will return 0 for an empty list" do
+      # Act-Assert
+      expect(@list.length).must_equal 0
+    end
+
+    it "will return the length for nonempty lists" do
+      # Arrange
+      count = 0
+      while count < 5
+        @list.add_first(count)
+        count += 1
+        # Act-Assert
+        expect(@list.length).must_equal count
+      end
+    end
+  end
+
+  describe "addLast & getLast" do
+    it "will add to the front if the list is empty" do
+      # Arrange
+      @list.add_last(1)
+      # Act-Assert
+      expect(@list.get_first).must_equal 1
+    end
+
+    it "will put new items to the rear of the list" do
+      # Arrange
+      @list.add_last(2)
+      # Act-Assert
+      expect(@list.length).must_equal 1
+      expect(@list.get_last).must_equal 2
+
+      # Arrange
+      @list.add_last(3)
+      # Act-Assert
+      expect(@list.get_first).must_equal 2
+      expect(@list.get_last).must_equal 3
+      expect(@list.length).must_equal 2
+
+      @list.add_last(4)
+      expect(@list.get_first).must_equal 2
+      expect(@list.get_last).must_equal 4
+      expect(@list.length).must_equal 3
+    end
+
+    it "will return `nil` for `get_last` if the list is empty" do
+      # Act-Assert
+      expect(@list.get_last).must_be_nil
+    end
+  end
+
+  describe "get_at_index" do
+    it "returns nil if the index is outside the bounds of the list" do
+      # Act-Assert
+      expect(@list.get_at_index(3)).must_be_nil
+    end
+
+    it "can retrieve an item at an index in the list" do
+      # Arrange
+      @list.add_first(1)
+      @list.add_first(2)
+      @list.add_first(3)
+      @list.add_first(4)
+
+      # Act-Assert
+      expect(@list.get_at_index(0)).must_equal 4
+      expect(@list.get_at_index(1)).must_equal 3
+      expect(@list.get_at_index(2)).must_equal 2
+      expect(@list.get_at_index(3)).must_equal 1
+    end
+  end
+
+  describe "max and min values" do
+    it "returns nil if the list is empty" do
+      # Act-Assert
+      expect(@list.find_max()).must_be_nil
+      expect(@list.find_min()).must_be_nil
+    end
+
+    it "can retrieve the max and min values in the list" do
+      # Arrange
+      count = 0
+      while count < 5
+        @list.add_first(count)
+        expect(@list.find_max).must_equal count
+        expect(@list.find_min).must_equal 0
+        count += 1
+      end
+      @list.add_last(100)
+      @list.add_first(-12)
+
+      # Act-Assert
+      expect(@list.find_max).must_equal 100
+      expect(@list.find_min).must_equal(-12)
+    end
+  end
+
+  describe "delete" do
+    it "delete from empty linked list is a no-op" do
+      # Assert
+      expect(@list.length).must_equal 0
+      # Act
+      @list.delete(4)
+      # Assert
+      expect(@list.length).must_equal 0
+    end
+
+    it "can delete valid values from list" do
+      # Arrange
+      @list.add_last(9)
+      @list.add_last(10)
+      @list.add_first(4)
+      @list.add_first(3)
+      @list.add_first(2)
+
+      # Act
+      # delete fist node (requires updating head)
+      @list.delete(2)
+
+      # Assert
+      expect(@list.get_first).must_equal 3
+      expect(@list.length).must_equal 4
+      expect(@list.get_last).must_equal 10
+      expect(@list.find_max).must_equal 10
+      expect(@list.find_min).must_equal 3
+
+      # Act (again)
+      # delete last node
+      @list.delete(10)
+      # Assert
+      expect(@list.get_first).must_equal 3
+      expect(@list.length).must_equal 3
+      expect(@list.get_last).must_equal 9
+      expect(@list.find_max).must_equal 9
+      expect(@list.find_min).must_equal 3
+
+      # delete fist node (requires updating head)
+      @list.delete(4)
+      expect(@list.get_first).must_equal 3
+      expect(@list.length).must_equal 2
+      expect(@list.get_last).must_equal 9
+      expect(@list.find_max).must_equal 9
+      expect(@list.find_min).must_equal 3
+    end
+  end
+
+  describe "nth_from_the_end" do
+    it "returns nil if n is outside the bounds of the list" do
+      # Act-Assert
+      expect(@list.find_nth_from_end(3)).must_be_nil
+    end
+
+    it "can retrieve an item at index n from the end in the list" do
+      # Arrange
+      @list.add_first(1)
+      @list.add_first(2)
+      @list.add_first(3)
+      @list.add_first(4)
+
+      # Act-Assert
+      expect(@list.find_nth_from_end(0)).must_equal 1
+      expect(@list.find_nth_from_end(1)).must_equal 2
+      expect(@list.find_nth_from_end(2)).must_equal 3
+      expect(@list.find_nth_from_end(3)).must_equal 4
+      expect(@list.find_nth_from_end(4)).must_be_nil
+    end
+  end
+
+  describe "reverse" do
+    it "can retrieve an item at index n from the end in the list" do
+      # Arrange
+      @list.add_first(4)
+      @list.add_first(3)
+      @list.add_first(2)
+      @list.add_first(1)
+
+      # Act
+      @list.reverse
+
+      # Assert
+      expect(@list.find_nth_from_end(0)).must_equal 1
+      expect(@list.find_nth_from_end(1)).must_equal 2
+      expect(@list.find_nth_from_end(2)).must_equal 3
+      expect(@list.find_nth_from_end(3)).must_equal 4
     end
+  end
 end