Brandon lent

README.md

@@ -5,7 +5,7 @@ Topics:
  * Doubly Linked Lists
  * Binary Search Trees
  * Heaps
-
+/comment
 Stretch Goals:
  * Generic Heaps
  * AVL Trees

binary_search_tree/binary_search_tree.py

@@ -1,17 +1,68 @@
 class BinarySearchTree:
-  def __init__(self, value):
-    self.value = value
-    self.left = None
-    self.right = None
+    def __init__(self, value):
+        self.value = value
+        self.left = None
+        self.right = None
 
-  def insert(self, value):
-    pass
+    def insert(self, value):
+        if value < self.value:
+            if not self.left:
+                self.left = BinarySearchTree(value)
+            else:
+                self.left.insert(value)
+        else:
+            if not self.right:
+                self.right = BinarySearchTree(value)
+            else:
+                self.right.insert(value)
 
-  def contains(self, target):
-    pass
+    def contains(self, target):
+        current_node = self
 
-  def get_max(self):
-    pass
+        while current_node is not None:
+            if target == current_node.value:
+                return True
+            elif current_node.left is None and current_node.right is None:
+                break
+            elif target < current_node.value:
+                current_node = current_node.left
+                print(current_node)
+                current_node.contains(target)
+            elif target > current_node.value:
+                current_node = current_node.right
+                print(current_node)
+                current_node.contains(target)
+        return False
 
-  def for_each(self, cb):
-    pass
+    def get_max(self):
+
+        max_value = self.value
+        current_node = self
+        while current_node:
+            if current_node.left is None and current_node.right is None:
+                break
+            elif current_node.right.value > max_value:
+                max_value = current_node.right.value
+                current_node = current_node.right
+                return current_node.get_max()
+            else:
+                current_node = current_node.right
+                return current_node.get_max()
+
+        return max_value
+
+    def for_each(self, cb):
+
+        current_node = self
+        left_node = self.left
+        right_node = self.right
+        cb(self.value)
+        if left_node is None and right_node is None:
+            return
+        elif left_node and right_node:
+            left_node.for_each(cb)
+            right_node.for_each(cb)
+        elif left_node is not None and right_node is None:
+            left_node.for_each(cb)
+        elif right_node is not None and left_node is None:
+            right_node.for_each(cb)

doubly_linked_list/doubly_linked_list.py

@@ -1,68 +1,154 @@
-"""Each ListNode holds a reference to its previous node
-as well as its next node in the List."""
 class ListNode:
-  def __init__(self, value, prev=None, next=None):
-    self.value = value
-    self.prev = prev
-    self.next = next
+    def __init__(self, value, prev=None, next=None):
+        self.value = value
+        self.prev = prev
+        self.next = next
 
-  """Wrap the given value in a ListNode and insert it
+    """Wrap the given value in a ListNode and insert it
   after this node. Note that this node could already
   have a next node it is point to."""
-  def insert_after(self, value):
-    current_next = self.next
-    self.next = ListNode(value, self, current_next)
-    if current_next:
-      current_next.prev = self.next
 
-  """Wrap the given value in a ListNode and insert it
+    def get_value(self):
+        return self.value
+
+    def insert_after(self, value):
+        current_next = self.next
+        self.next = ListNode(value, self, current_next)
+        if current_next:
+            current_next.prev = self.next
+
+    """Wrap the given value in a ListNode and insert it
   before this node. Note that this node could already
   have a previous node it is point to."""
-  def insert_before(self, value):
-    current_prev = self.prev
-    self.prev = ListNode(value, current_prev, self)
-    if current_prev:
-      current_prev.next = self.prev
 
-  """Rearranges this ListNode's previous and next pointers
+    def insert_before(self, value):
+        current_prev = self.prev
+        self.prev = ListNode(value, current_prev, self)
+        if current_prev:
+            current_prev.next = self.prev
+
+    """Rearranges this ListNode's previous and next pointers
   accordingly, effectively deleting this ListNode."""
-  def delete(self):
-    if self.prev:
-      self.prev.next = self.next
-    if self.next:
-      self.next.prev = self.prev
+
+    def delete(self):
+        if self.prev:
+            self.prev.next = self.next
+        if self.next:
+            self.next.prev = self.prev
+
 
 """Our doubly-linked list class. It holds references to
 the list's head and tail nodes."""
+
+
 class DoublyLinkedList:
-  def __init__(self, node=None):
-    self.head = node
-    self.tail = node
-    self.length = 1 if node is not None else 0
+    def __init__(self, node=None):
+        self.head = node
+        self.tail = node
+        self.length = 1 if node is not None else 0
+
+    def __len__(self):
+        return self.length
+
+    def add_to_head(self, value):
+        new_node = ListNode(value)
+        if not self.head and not self.tail:
+            self.head = new_node
+            self.tail = new_node
+            self.length += 1
+        else:
+            self.head.insert_before(value)
+            self.head = self.head.prev
+            self.length += 1
+
+    def remove_from_head(self):
+        if self.head == self.tail:
+            deleted_value = self.head.value
+            self.head = None
+            self.tail = None
+            self.length -= 1
+            return deleted_value
+        else:
+            deleted_value = self.head.value
+            self.head = self.head.next
+            self.head.prev = None
+            self.length -= 1
+            return deleted_value
+
+    def add_to_tail(self, value):
+        new_node = ListNode(value)
+
+        if not self.head and not self.tail:
+            self.head = new_node
+            self.tail = new_node
+            self.length += 1
+        else:
+            self.tail.insert_after(value)
+            self.tail = self.tail.next
+            self.tail.next = None
+            self.length += 1
+
+    def remove_from_tail(self):
+        if self.head == self.tail:
+            deleted_value = self.tail.value
+            self.head = None
+            self.tail = None
+            self.length -= 1
+            return deleted_value
+        else:
+            deleted_value = self.tail.value
+            self.tail = self.tail.prev
+            self.tail = None
+            self.length -= 1
+            return deleted_value
+
+    def move_to_front(self, node):
+        self.add_to_head(node.value)
+        node.delete()
+        self.length -= 1
+
+    def move_to_end(self, node):
+        if node.value == self.head:
+            self.add_to_tail(node.value)
+            self.remove_from_head()
+
+        else:
+            self.add_to_tail(node.value)
+            self.remove_from_head()
 
-  def __len__(self):
-    return self.length
+    def delete(self, node):
+        if node.prev is None:
+            self.remove_from_head()
+        elif node.next is None:
+            self.remove_from_tail()
+        else:
+            self.delete(node)
+            self.length -= 1
 
-  def add_to_head(self, value):
-    pass
+    def get_max(self):
+        max_value = self.head.value
+        if self.length == 1 and self.head == self.tail:
+            return self.head.value
+        elif self.length > 1:
+            current_node = self.head
+            while current_node is not None:
+                if current_node.next is None:
+                    break
+                elif current_node.next.value > max_value:
+                    max_value = current_node.next.value
+                current_node = current_node.next
+        else:
+            return 0
 
-  def remove_from_head(self):
-    pass
+        return max_value
 
-  def add_to_tail(self, value):
-    pass
 
-  def remove_from_tail(self):
-    pass
+dblList = DoublyLinkedList()
 
-  def move_to_front(self, node):
-    pass
+dblList.add_to_head(2)
+dblList.add_to_head(55)
+dblList.add_to_head(60)
+dblList.add_to_tail(30)
 
-  def move_to_end(self, node):
-    pass
 
-  def delete(self, node):
-    pass
-
-  def get_max(self):
-    pass
+print(dblList.get_max())

heap/max_heap.py

@@ -1,21 +1,27 @@
 class Heap:
-  def __init__(self):
-    self.storage = []
+    def __init__(self):
+        self.storage = []
 
-  def insert(self, value):
-    pass
+    def insert(self, value):
+        pass
 
-  def delete(self):
-    pass
+    def delete(self):
+        pass
 
-  def get_max(self):
-    pass
+    def get_max(self):
+        pass
 
-  def get_size(self):
-    pass
+    def get_size(self):
+        pass
 
-  def _bubble_up(self, index):
-    pass
+    def _bubble_up(self, index):
+        while index > 0:
+            parent = (index-1) // 2
+            if self.storage[index] > self.storage[parent]:
+                self.storage[index], self.storage[parent] = self.storage[parent], self.storage[index]
+                index = parent
+            else:
+                break
 
-  def _sift_down(self, index):
-    pass
+    def _sift_down(self, index):
+        pass

queue/linked_list.py

@@ -0,0 +1,59 @@
+class Node:
+    def __init__(self, value, next_node=None):
+        self.value = value
+        self.next_node = next_node
+
+    def get_value(self):
+        return self.value
+
+    def get_next(self):
+        return self.next_node
+
+    def set_next(self, new_next):
+        self.next_node = new_next
+
+
+class LinkedList:
+    def __init__(self):
+        self.head = None
+        self.tail = None
+
+    def add_to_tail(self, value):
+        new_node = Node(value)
+
+        if not self.head and not self.tail:
+            self.head = new_node
+            self.tail = new_node
+        else:
+            self.tail.set_next(new_node)
+            self.tail = new_node
+
+    def remove_head(self):
+
+        if not self.head and not self.tail:
+            return None
+
+        if self.head == self.tail:
+            old_head = self.head
+            self.head = None
+            self.tail = None
+
+            return old_head.get_value()
+        else:
+            old_head = self.head
+            self.head = self.head.get_next()
+            return old_head.get_value()
+
+    def contain(self, value):
+        if not self.head and not self.tail:
+            return None
+
+        current = self.head
+
+        while current:
+            if current.get_value() == value:
+                return True
+
+            current = current.get_next()
+
+        return False