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 Summary

Constructors

Constructor and Description
MyCircularQueue(int k)

Method Summary

Modifier and Type	Method and Description
boolean	deQueue()
boolean	enQueue(int value)
int	front()
boolean	isEmpty()
boolean	isFull()
int	rear()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MyCircularQueue

public MyCircularQueue(int k)

Method Detail

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()