Package g0601_0700.s0622_design_circular_queue

Class MyCircularQueue

java.lang.Object
g0601_0700.s0622_design_circular_queue.MyCircularQueue
public class MyCircularQueue extends Object
622 - Design Circular Queue.

Medium

Design your implementation of the circular queue. The circular queue is a linear data structure in which the operations are performed based on FIFO (First In First Out) principle and the last position is connected back to the first position to make a circle. It is also called “Ring Buffer”.

One of the benefits of the circular queue is that we can make use of the spaces in front of the queue. In a normal queue, once the queue becomes full, we cannot insert the next element even if there is a space in front of the queue. But using the circular queue, we can use the space to store new values.

Implementation the MyCircularQueue class:

  • MyCircularQueue(k) Initializes the object with the size of the queue to be k.
  • int Front() Gets the front item from the queue. If the queue is empty, return -1.
  • int Rear() Gets the last item from the queue. If the queue is empty, return -1.
  • boolean enQueue(int value) Inserts an element into the circular queue. Return true if the operation is successful.
  • boolean deQueue() Deletes an element from the circular queue. Return true if the operation is successful.
  • boolean isEmpty() Checks whether the circular queue is empty or not.
  • boolean isFull() Checks whether the circular queue is full or not.

You must solve the problem without using the built-in queue data structure in your programming language.

Example 1:

Input [“MyCircularQueue”, “enQueue”, “enQueue”, “enQueue”, “enQueue”, “Rear”, “isFull”, “deQueue”, “enQueue”, “Rear”] [[3], [1], [2], [3], [4], [], [], [], [4], []]

Output: [null, true, true, true, false, 3, true, true, true, 4]

Explanation: MyCircularQueue myCircularQueue = new MyCircularQueue(3); myCircularQueue.enQueue(1); // return True myCircularQueue.enQueue(2); // return True myCircularQueue.enQueue(3); // return True myCircularQueue.enQueue(4); // return False myCircularQueue.Rear(); // return 3 myCircularQueue.isFull(); // return True myCircularQueue.deQueue(); // return True myCircularQueue.enQueue(4); // return True myCircularQueue.Rear(); // return 4

Constraints:

  • 1 <= k <= 1000
  • 0 <= value <= 1000
  • At most 3000 calls will be made to enQueue, deQueue, Front, Rear, isEmpty, and isFull.

  • Constructor Details

    • MyCircularQueue

      public MyCircularQueue(int k)

  • Method Details

    • enQueue

      public boolean enQueue(int value)

    • deQueue

      public boolean deQueue()

    • rear

      public int rear()

    • front

      public int front()

    • isEmpty

      public boolean isEmpty()

    • isFull

      public boolean isFull()