diff --git a/linked_list/linked_list.py b/linked_list/linked_list.py
index 63993214..91d15a5e 100644
--- a/linked_list/linked_list.py
+++ b/linked_list/linked_list.py
@@ -1,79 +1,159 @@
 
 # Defines a node in the singly linked list
-class Node:
+from types import new_class
+
 
-    def __init__(self, value, next_node = None):
+class Node:
+    def __init__(self, value, next_node = None, prev_node = None):
         self.value = value
         self.next = next_node
+        self.previous = prev_node #This line because this is a doubly linked list
 
 # Defines the singly linked list
 class LinkedList:
     def __init__(self):
-      self.head = None # keep the head private. Not accessible outside this class
+        self.head = None # keep the head private. Not accessible outside this class
+        self.tail = None
 
     # returns the value in the first node
     # returns None if the list is empty
-    # Time Complexity: ?
-    # Space Complexity: ?
+    # Time Complexity: O(1)
+    # Space Complexity: O(1)
     def get_first(self):
-        pass
-
+        if self.head is None:
+            return None
+        return self.head.value
 
     # 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: ?
+    # Time Complexity: O(1)
+    # Space Complexity: O(1)
     def add_first(self, value):
-        pass
+        if self.head is None:
+            self.head = self.tail = Node(value)
+
+        else:
+            new_node = Node(value, self.head)
+            self.head.previous = new_node
+            self.head = new_node
 
     # method to find if the linked list contains a node with specified value
     # returns true if found, false otherwise
-    # Time Complexity: ?
-    # Space Complexity: ?
+    # Time Complexity: O(n)
+    # Space Complexity: O(1)
     def search(self, value):
-        pass
+        current_node = self.head
+        
+        if current_node == None:
+            return False
+        
+        while current_node: 
+            if current_node.value == value:
+                return True
+            current_node = current_node.next
+        return False
 
     # method that returns the length of the singly linked list
-    # Time Complexity: ?
-    # Space Complexity: ?
+    # Time Complexity: O(n)
+    # Space Complexity: O(1)
     def length(self):
-        pass
+        len_ll = 0
+        current_node = self.head
+
+        while current_node != None:
+            len_ll +=1
+            current_node = current_node.next
+        return len_ll
 
     # method that returns the value at a given index in the linked list
     # index count starts at 0
     # returns None if there are fewer nodes in the linked list than the index value
-    # Time Complexity: ?
-    # Space Complexity: ?
+    # Time Complexity: O(n)
+    # Space Complexity: O(1)
     def get_at_index(self, index):
-        pass
+        count = 0
+        current_node = self.head
+
+        while current_node != None:
+            if count == index:
+                return current_node.value
+            count += 1
+            current_node = current_node.next
+        return None
 
     # method that returns the value of the last node in the linked list
     # returns None if the linked list is empty
-    # Time Complexity: ?
-    # Space Complexity: ?
+    # Time Complexity: O(n)
+    # Space Complexity: O(1)
     def get_last(self):
-        pass
+        head = self.head
+        if head == None:
+            return None
+
+        while head.next:
+            head = head.next
+        
+        return head.value
 
     # method that inserts a given value as a new last node in the linked list
-    # Time Complexity: ?
-    # Space Complexity: ?
+    # Time Complexity: O(n)
+    # Space Complexity: O(1)
     def add_last(self, value):
-        pass
+        if self.head == None:
+            self.add_first(value)
+        else:
+            new_node = Node(value)
+            current_node = self.head
+
+            while current_node.next:
+                current_node = current_node.next
+            current_node.next = new_node
+
 
     # method to return the max value in the linked list
     # returns the data value and not the node
     def find_max(self):
-        pass
+        if self.head == None:
+            return None
+        
+        head = self.head
+        max_value = self.get_at_index(0)
+
+        while head:
+            if head.value > max_value:
+                max_value = head.value
+            head = head.next
+
+        return max_value
 
     # method to delete the first node found with specified value
-    # Time Complexity: ?
-    # Space Complexity: ?
+    # Time Complexity: O(n)
+    # Space Complexity: O(n)
     def delete(self, value):
-        pass
+
+        new = self.head
+
+        if new != None:
+            if new.value == value:
+                self.head = new.next
+                new = None
+                return
+
+            while new:
+                if new.value == value:
+                    break
+                prev = new
+                new = new.next
+            if new == None:
+                return
+            
+            prev.next = new.next
+            new = None
+
 
     # method to print all the values in the linked list
-    # Time Complexity: ?
-    # Space Complexity: ?
+    # Time Complexity: O(n)
+    # Space Complexity: O(1)
     def visit(self):
         helper_list = []
         current = self.head
@@ -86,11 +166,22 @@ def visit(self):
 
     # 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: ?
+    # Time Complexity: O(n)
+    # Space Complexity: O(1)
     def reverse(self):
-        pass
-  
+        if not self.head:
+            return
+        current_node = self.head
+        previous_node = None
+
+        while current_node:
+            next = current_node.next
+            current_node.next = previous_node
+            previous_node = current_node
+            current_node = next
+
+        self.head = previous_node
+
     ## Advanced/ Exercises
     # returns the value at the middle element in the singly linked list
     # Time Complexity: ?