Brittany - Stacks and Queues

stacks_queues/linked_list.py

@@ -48,7 +48,7 @@ def remove_first(self):
 
 
     def empty(self):
-      return not self.head
+        return not self.head
 
     # method to find if the linked list contains a node with specified value
     # returns true if found, false otherwise

stacks_queues/queue.py

@@ -1,4 +1,7 @@
 
+from logging import raiseExceptions
+
+
 INITIAL_QUEUE_SIZE = 20
 
 class QueueFullException(Exception):
@@ -7,6 +10,11 @@ class QueueFullException(Exception):
 class QueueEmptyException(Exception):
     pass
 
+# queue = Queue()
+
+# queue.enqueue(1)
+# print(str(queue)) # [Object Queue]
+
 class Queue:
 
     def __init__(self):
@@ -15,22 +23,30 @@ def __init__(self):
         self.front = -1
         self.rear = -1
         self.size = 0
-
-
+
     def enqueue(self, element):
         """ Adds an element to the Queue
             Raises a QueueFullException if all elements
             In the store are occupied
             returns None
-        """
-        pass
+        """ 
+        if self.get_size() + 1 > INITIAL_QUEUE_SIZE:
+            raise QueueFullException("Queue is full")
+
+        queue = self.store
+        if queue != None:
+            queue.append(element)
+
 
     def dequeue(self):
         """ Removes and returns an element from the Queue
             Raises a QueueEmptyException if 
             The Queue is empty.
         """
-        pass
+        result = self.store.pop(0)
+        if result is None:
+            return self.dequeue()
+        return result
 
     def front(self):
         """ Returns an element from the front
@@ -40,6 +56,13 @@ def front(self):
         pass
 
 
+    def get_size(self):
+        """ Returns the number of elements in
+            The Queue
+        """
+        list_where_not_none = [x for x in self.store if x is not None]
+        return len(list_where_not_none)
+
     def size(self):
         """ Returns the number of elements in
             The Queue
@@ -50,12 +73,13 @@ def empty(self):
         """ Returns True if the Queue is empty
             And False otherwise.
         """
-        pass
+        return self.get_size() == 0
 
     def __str__(self):
         """ Returns the Queue in String form like:
             [3, 4, 7]
             Starting with the front of the Queue and
             ending with the rear of the Queue.
         """
-        pass
+        return str([x for x in self.store if x is not None])
+

stacks_queues/stack.py

@@ -12,7 +12,7 @@ def push(self, element):
         """ Adds an element to the top of the Stack.
             Returns None
         """
-        pass
+        self.store.add_last(element)
 
     def pop(self):
         """ Removes an element from the top
@@ -21,13 +21,13 @@ def pop(self):
             The Stack is empty.
             returns None
         """
-        pass
+        return self.store.remove_last()
 
     def empty(self):
         """ Returns True if the Stack is empty
             And False otherwise
         """
-        pass
+        return self.store.length() == 0
 
     def __str__(self):
         """ Returns the Stack in String form like: