Can Someone help me with this PYTHON problem! please answer with code!

Overview

For this assignment you will implement a circular, array-backed queue data structure.

In the following class, which you are to complete, the backing array will be created and populated with Nones in the __init__ method, and the head and tail indexes set to sentinel values (you shouldn't need to modify __init__). Enqueueing and Dequeueing items will take place at the tail and head, with tail and head tracking the position of the most recently enqueued item and that of the next item to dequeue, respectively. To simplify testing, your implementation should make sure that when dequeuing an item its slot in the array is reset to None, and when the queue is emptied its head and tail attributes should be set to -1.

Because of the fixed size backing array, the enqueue operation is defined to raise a RuntimeError when the queue is full the same exception should be raised when dequeue is called on an empty queue.

Finally, the resize method will allow the array underlying the queue to be increased in size. It is up to you how to implement this (you can either leave the elements in their current positions, though this may require "unwrapping" elements, or you can simply move all elements towards the front of the array). You may assume that resize will only be called with a value greater than the current length of the underlying array.

In [ ]:

class Queue: 

 def __init__(self, limit=10): 

 self.data = [None] * limit 

 self.head = -1 

 self.tail = -1 

 # YOUR CODE HERE 

 raise NotImplementedError() 

 def enqueue(self, val): 

 # YOUR CODE HERE 

 raise NotImplementedError() 

 def dequeue(self): 

 # YOUR CODE HERE 

 raise NotImplementedError() 

 def resize(self, newsize): 

 assert(len(self.data) < newsize) 

 # YOUR CODE HERE 

 raise NotImplementedError() 

 def empty(self): 

 # YOUR CODE HERE 

 raise NotImplementedError() 

 def __bool__(self): 

 return not self.empty() 

 def __str__(self): 

 if not(self): 

 return '' 

 return ', '.join(str(x) for x in self) 

 def __repr__(self): 

 return str(self) 

 def __iter__(self): 

 # YOUR CODE HERE 

 raise NotImplementedError() 

. . .

In [ ]:

# (5 points) 

from unittest import TestCase 

tc = TestCase() 

q = Queue(5) 

tc.assertEqual(q.data, [None] * 5) 

for i in range(5): 

 q.enqueue(i) 

with tc.assertRaises(RuntimeError): 

 q.enqueue(5) 

for i in range(5): 

 tc.assertEqual(q.dequeue(), i) 

tc.assertTrue(q.empty()) 

. . .

In [ ]:

# (5 points) 

from unittest import TestCase 

tc = TestCase() 

q = Queue(10) 

for i in range(6): 

 q.enqueue(i) 

tc.assertEqual(q.data.count(None), 4) 

for i in range(5): 

 q.dequeue() 

tc.assertFalse(q.empty()) 

tc.assertEqual(q.data.count(None), 9) 

tc.assertEqual(q.head, q.tail) 

tc.assertEqual(q.head, 5) 

for i in range(9): 

 q.enqueue(i) 

with tc.assertRaises(RuntimeError): 

 q.enqueue(10) 

for x, y in zip(q, [5] + list(range(9))): 

 tc.assertEqual(x, y) 

tc.assertEqual(q.dequeue(), 5) 

for i in range(9): 

 tc.assertEqual(q.dequeue(), i) 

tc.assertTrue(q.empty()) 

. . .

In [ ]:

# (5 points) 

from unittest import TestCase 

tc = TestCase() 

q = Queue(5) 

for i in range(5): 

 q.enqueue(i) 

for i in range(4): 

 q.dequeue() 

for i in range(5, 9): 

 q.enqueue(i) 

with tc.assertRaises(RuntimeError): 

 q.enqueue(10) 

q.resize(10) 

for x, y in zip(q, range(4, 9)): 

 tc.assertEqual(x, y) 

for i in range(9, 14): 

 q.enqueue(i) 

for i in range(4, 14): 

 tc.assertEqual(q.dequeue(), i) 

tc.assertTrue(q.empty()) 

tc.assertEqual(q.head, -1)