diff --git a/lib/linked_list.rb b/lib/linked_list.rb
index 0de1ee00..b7dbb694 100644
--- a/lib/linked_list.rb
+++ b/lib/linked_list.rb
@@ -1,4 +1,4 @@
-
+require "pry"
 # Defines a node in the singly linked list
 class Node
   attr_reader :data # allow external entities to read value but not write
@@ -12,150 +12,266 @@ 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: ?
-    # Space Complexity: ?
-    def add_first(value)
-      raise NotImplementedError
-    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)
+    node = Node.new(value)
+    node.next = @head
+    @head = node
+  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
+  # 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
+    while current != nil
+      return true if current.data == value
+      current = current.next
     end
+    return false
+  end
 
-    # method to return the max value in the linked list
-    # returns the data value and not the node
-    def find_max
-      raise NotImplementedError
+  # 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(n)
+  def find_max
+    return nil if !@head
+    current = @head
+    max = -(Float::INFINITY)
+    while current != nil
+      if current.data > max
+        max = current.data
+      end
+      current = current.next
     end
+    return max
+  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
+  # 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(1)
+  def find_min
+    return nil if !@head
+    current = @head
+    min = Float::INFINITY
+    while current != nil
+      if current.data < min
+        min = current.data
+      end
+      current = current.next
     end
+    return min
+  end
 
-
-    # method that returns the length of the singly linked list
-    # Time Complexity: ?
-    # Space Complexity: ?
-    def length
-      raise NotImplementedError
+  # method that returns the length of the singly linked list
+  # Time Complexity: O(n)
+  # Space Complexity: O(1)
+  def length
+    counter = 0
+    current = @head
+    while current != nil
+      counter += 1
+      current = current.next
     end
+    return counter
+  end
 
-    # 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
+  # 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)
+    i = 0
+    current = @head
+    while current != nil
+      return current.data if index == i
+      i += 1
+      current = current.next
     end
+    return nil
+  end
 
-    # method to print all the values in the linked list
-    # Time Complexity: ?
-    # Space Complexity: ?
-    def visit
-      raise NotImplementedError
+  # method to print all the values in the linked list
+  # Time Complexity: O(n)
+  # Space Complexity: O(1)
+  def visit
+    current = @head
+    while current != nil
+      puts current.data
+      current = current.next
     end
+  end
 
-    # method to delete the first node found with specified value
-    # Time Complexity: ?
-    # Space Complexity: ?
-    def delete(value)
-      raise NotImplementedError
+  # method to delete the first node found with specified value
+  # Time Complexity: O(1)
+  # Space Complexity: O(1)
+  def delete(value)
+    return nil if !@head
+    if @head.data == value
+      @head = @head.next
+      return
     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
+    current = @head
+    while current != nil
+      if current.next.data == value
+        current.next = current.next.next
+        return
+      end
+      current = current.next
     end
+  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
+    prev = nil
+    next_node = nil
+    current = @head
+    while current != nil
+     
+      next_node = current.next
+      current.next = prev
+      prev = current
+      current = next_node
+    end
+    @head = prev
+  end
 
-    ## Advanced Exercises
-    # returns the value at the middle element in the singly linked list
-    # Time Complexity: ?
-    # Space Complexity: ?
-    def find_middle_value
-      raise NotImplementedError
+  ## 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
+    return nil if !@head
+    slow = @head
+    fast = @head
+    while fast.next != nil
+      slow = slow.next
+      fast = fast.next.next
     end
+    return slow.data
+  end
 
-    # 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
+  # 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
+    current = @head
+    index = 1
+    while current != nil
+      if length - index == n
+        return current.data
+      end
+      index += 1
+      current = current.next
     end
+    return nil
+  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
+  # 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
+    return false if !@head || @head.next = nil
+    slow = @head
+    fast = @head
+    while fast != nil
+      slow = slow.next
+      fast = fast.next
+      if fast != nil
+        fast = fast.next
+      end
+      return true if fast == slow
     end
+    return false
+  end
 
+  # Additional Exercises
+  # returns the value in the first node
+  # returns nil if the list is empty
+  # Time Complexity: O(1)
+  # Space Complexity: O(1)
+  def get_first
+    return @head.data if @head
+    return nil
+  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
+  # method that inserts a given value as a new last node in the linked list
+  # Time Complexity: O(1)
+  # Space Complexity: O(1)
+  def add_last(value)
+    new_node = Node.new(value)
+    if !@head
+      @head = new_node
+      return
     end
-
-    # 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
+    current = @head
+    while current.next != nil
+      current = current.next
     end
+    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: ?
-    # Space Complexity: ?
-    def get_last
-      raise NotImplementedError
+  # method that returns the value of the last node in the linked list
+  # returns nil if the linked list is empty
+  # Time Complexity: O(1)
+  # Space Complexity: O(1)
+  def get_last
+    return nil if @head == nil
+    current = @head
+    while current.next != nil
+      current = current.next
     end
+    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: ?
-    # Space Complexity: ?
-    def insert_ascending(value)
-      raise NotImplementedError
+  # 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 
     end
+    current = @head
+    while current.next && current.next.value <= value
+      current = current.next
+    end
+    new_node.next = current.next
+    current.next = new_node
+  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
-
-      # navigate to last node
-      current = @head
-      while current.next != nil
-          current = current.next
-      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
 
-      current.next = @head # make the last node link to first node
+    # 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