mac cedar

stacks_queues/queue.py

@@ -1,61 +1,98 @@
-
 INITIAL_QUEUE_SIZE = 20
 
+
 class QueueFullException(Exception):
     pass
 
+
 class QueueEmptyException(Exception):
     pass
 
-class Queue:
 
+class Queue:
     def __init__(self):
         self.store = [None] * INITIAL_QUEUE_SIZE
         self.buffer_size = INITIAL_QUEUE_SIZE
         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
+        """Adds an element to the Queue
+        Raises a QueueFullException if all elements
+        In the store are occupied
+        returns None
         """
-        pass
+        if self.size == len(self.store):
+            raise QueueFullException
+
+        if self.front == -1:
+            self.front = 0
+            self.rear = 0
+            self.store[self.rear] = element
+
+        elif self.rear == len(self.store) - 1:
+            self.rear = 0
+            self.store[self.rear] = element
+        else:
+            self.rear += 1
+            self.store[self.rear] = element
+        self.size += 1
 
     def dequeue(self):
-        """ Removes and returns an element from the Queue
-            Raises a QueueEmptyException if 
-            The Queue is empty.
+        """Removes and returns an element from the Queue
+        Raises a QueueEmptyException if
+        The Queue is empty.
         """
-        pass
+        if self.empty():
+            raise QueueEmptyException
+
+        element = self.store[self.front]
+        self.store[self.front] = None
+
+        if self.front == self.rear:
+            self.front = -1
+            self.rear = -1
+
+        elif self.front == len(self.store) - 1:
+            self.front = 0
+        else:
+            self.front += 1
+        self.size -= 1
+        return element
 
     def front(self):
-        """ Returns an element from the front
-            of the Queue and None if the Queue
-            is empty.  Does not remove anything.
+        """Returns an element from the front
+        of the Queue and None if the Queue
+        is empty.  Does not remove anything.
         """
-        pass
-
+        if self.size > 0:
+            return self.store[self.front]
 
     def size(self):
-        """ Returns the number of elements in
-            The Queue
+        """Returns the number of elements in
+        The Queue
         """
-        pass
+        return self.size
 
     def empty(self):
-        """ Returns True if the Queue is empty
-            And False otherwise.
+        """Returns True if the Queue is empty
+        And False otherwise.
         """
-        pass
+        return self.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.
+        """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
+        q = []
+        start = self.front
+        while len(q) < self.size:
+            q.append(self.store[start])
+            if start < len(self.store) - 1:
+                start += 1
+            else:
+                start = 0
+        return str(q)

stacks_queues/stack.py

@@ -1,38 +1,39 @@
 from stacks_queues.linked_list import LinkedList
 
+
 class StackEmptyException(Exception):
     pass
 
-class Stack:
 
+class Stack:
     def __init__(self):
         self.store = LinkedList()
 
     def push(self, element):
-        """ Adds an element to the top of the Stack.
-            Returns None
+        """Adds an element to the top of the Stack.
+        Returns None
         """
-        pass
+        self.store.add_first(element)
 
     def pop(self):
-        """ Removes an element from the top
-            Of the Stack
-            Raises a StackEmptyException if
-            The Stack is empty.
-            returns None
+        """Removes an element from the top
+        Of the Stack
+        Raises a StackEmptyException if
+        The Stack is empty.
+        returns None
         """
-        pass
+        return self.store.remove_first() if not self.empty() else StackEmptyException()
 
     def empty(self):
-        """ Returns True if the Stack is empty
-            And False otherwise
+        """Returns True if the Stack is empty
+        And False otherwise
         """
-        pass
+        return self.store.empty()
 
     def __str__(self):
-        """ Returns the Stack in String form like:
-            [3, 4, 7]
-            Starting with the top of the Stack and
-            ending with the bottom of the Stack.
+        """Returns the Stack in String form like:
+        [3, 4, 7]
+        Starting with the top of the Stack and
+        ending with the bottom of the Stack.
         """
-        pass
+        return self.store.visit()