qs

Author: aish21

Diff for: Practice Concepts/Data Structures/dequeue.py

@@ -0,0 +1,40 @@
+from collections import deque
+
+class Deque:
+    def __init__(self):
+        self.deque = deque()
+
+    def enqueue_front(self, item):
+        self.deque.appendleft(item)  # Add item to the front
+
+    def enqueue_rear(self, item):
+        self.deque.append(item)  # Add item to the rear
+
+    def dequeue_front(self):
+        if not self.is_empty():
+            return self.deque.popleft()  # Remove and return the front item
+        raise IndexError("Dequeue from an empty deque")
+
+    def dequeue_rear(self):
+        if not self.is_empty():
+            return self.deque.pop()  # Remove and return the rear item
+        raise IndexError("Dequeue from an empty deque")
+
+    def is_empty(self):
+        return len(self.deque) == 0
+
+    def size(self):
+        return len(self.deque)
+
+# Test cases
+deque = Deque()
+deque.enqueue_front(10)
+deque.enqueue_front(20)
+deque.enqueue_rear(30)
+assert deque.dequeue_front() == 20
+assert deque.dequeue_rear() == 30
+assert deque.size() == 1
+assert deque.is_empty() == False
+assert deque.dequeue_front() == 10
+assert deque.is_empty() == True
+assert deque.size() == 0

Diff for: Practice Concepts/Data Structures/priority_q.py

@@ -0,0 +1,45 @@
+import heapq
+
+class PriorityQueue:
+    def __init__(self):
+        self.queue = []
+
+    def enqueue(self, item):
+        heapq.heappush(self.queue, item)  # Push item while maintaining heap order
+
+    def dequeue(self):
+        if not self.is_empty():
+            return heapq.heappop(self.queue)  # Remove and return the smallest item
+        raise IndexError("Dequeue from an empty queue")
+
+    def is_empty(self):
+        return len(self.queue) == 0
+
+    def size(self):
+        return len(self.queue)
+
+    def front(self):
+        if not self.is_empty():
+            return self.queue[0]
+        raise IndexError("Front from an empty queue")
+    
+    def rear(self):
+        if not self.is_empty():
+            return self.queue[-1]
+        raise IndexError("Rear from an empty queue")
+
+# Test Cases
+queue = PriorityQueue()
+queue.enqueue(30)
+queue.enqueue(10)
+queue.enqueue(20)
+assert queue.front() == 10
+assert queue.rear() == 20
+assert queue.dequeue() == 10
+assert queue.front() == 20
+assert queue.rear() == 30
+assert queue.dequeue() == 20
+assert queue.front() == 30
+assert queue.rear() == 30
+assert queue.dequeue() == 30
+assert queue.is_empty() == True

Diff for: README.md

@@ -122,7 +122,7 @@
     - Space: O(n)
     - Time Complexities (Enqueue, Dequeue, Peek): O(1)
 
-  - Priority Queue (TODO)
+  - [Priority Queue](/Practice%20Concepts/Data%20Structures/priority_q.py)
 
     - Each element is linked with a priority value - served on the basis of their priority.
     - If elements have the same priority, they are then served according to their order in the queue.
@@ -131,7 +131,7 @@
     - Space: O(n)
     - Time Complexities (Enqueue, Dequeue, Peek): O(logn), O(1)
 
-  - Deque (Double Ended Queues)
+  - [Deque (Double Ended Queues)](/Practice%20Concepts/Data%20Structures/dequeue.py)
     - Flexible, allowing addition and removal from both ends.
     - Space: O(n)
     - Time Complexities (Enqueue, Dequeue, Peek): O(1)