Maria M. - Scissors

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 +15,84 @@ 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 == self.buffer_size:
+            raise QueueFullException('Queue is full')
+
+        elif self.front == -1:
+            self.front = 0
+            self.rear = 0
+            self.store[self.rear] = element
+            self.size += 1
+            return self.store
+
+        else:
+            self.rear = (self.rear + 1) % self.buffer_size
+            self.store[self.rear] = element
+            self.size += 1
+            return self.store
+
 
     def dequeue(self):
         """ Removes and returns an element from the Queue
             Raises a QueueEmptyException if 
             The Queue is empty.
         """
-        pass
+        if self.front == -1:
+            raise QueueEmptyException('Queue is empty')
+
+        else:
+            element = self.store[self.front]
+            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.empty(): 
+            return None 
+
+        else:
+            return self.store[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
+        else:
+            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
+
+        queue_list = []
+
+        if self.empty():
+            return str(queue_list)
+
+        for element in range(self.front, self.front + self.size):
+            element = element % self.buffer_size
+            queue_list.append(self.store[element])
+        return str(queue_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 +21,18 @@ def pop(self):
             The Stack is empty.
             returns None
         """
-        pass
+        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)