Pine-Alma

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

@@ -15,47 +15,81 @@ 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.size == 0:
+            self.front = 0
+        elif self.size == self.buffer_size:
+            raise QueueFullException
+
+        self.rear = (self.rear + 1) % self.buffer_size
+        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.
         """
-        pass
+        if self.size == 0:
+            raise QueueEmptyException
+        else:
+            element = self.store[self.front]
+            self.store[self.front] = None
+            self.front = (self.front + 1) % self.buffer_size
+            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.
         """
-        pass
+        if self.size == 0:
+            return None
+        else:
+            return self.front
 
 
     def size(self):
         """ 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.
         """
-        pass
+        if self.size == 0:
+            return True
+        return False
 
     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
+        list = []
+
+        if self.size == 0:
+            return list
+
+        current = self.front
+
+        while current != self.rear:
+            if current != None:
+                list.append(self.store[current])
+                current = (current + 1) % self.buffer_size
+
+        list.append(self.store[self.rear])
+
+        return str(list)

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_first(element)
 
     def pop(self):
         """ Removes an element from the top
@@ -21,18 +21,21 @@ def pop(self):
             The Stack is empty.
             returns None
         """
-        pass
+        if self.store.head is None:
+            raise StackEmptyException
+        return self.store.remove_first()
+
 
     def empty(self):
         """ 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.
         """
-        pass
+        return str(self.store)