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.<p>Medium</p> <p>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 &ldquo;Ring Buffer&rdquo;.</p> <p>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.</p> <p>Implementation the <code>MyCircularQueue</code> class:</p> <ul> <li><code>MyCircularQueue(k)</code> Initializes the object with the size of the queue to be <code>k</code>.</li> <li><code>int Front()</code> Gets the front item from the queue. If the queue is empty, return <code>-1</code>.</li> <li><code>int Rear()</code> Gets the last item from the queue. If the queue is empty, return <code>-1</code>.</li> <li><code>boolean enQueue(int value)</code> Inserts an element into the circular queue. Return <code>true</code> if the operation is successful.</li> <li><code>boolean deQueue()</code> Deletes an element from the circular queue. Return <code>true</code> if the operation is successful.</li> <li><code>boolean isEmpty()</code> Checks whether the circular queue is empty or not.</li> <li><code>boolean isFull()</code> Checks whether the circular queue is full or not.</li> </ul> <p>You must solve the problem without using the built-in queue data structure in your programming language.</p> <p><strong>Example 1:</strong></p> <p><strong>Input</strong> [&ldquo;MyCircularQueue&rdquo;, &ldquo;enQueue&rdquo;, &ldquo;enQueue&rdquo;, &ldquo;enQueue&rdquo;, &ldquo;enQueue&rdquo;, &ldquo;Rear&rdquo;, &ldquo;isFull&rdquo;, &ldquo;deQueue&rdquo;, &ldquo;enQueue&rdquo;, &ldquo;Rear&rdquo;] [[3], [1], [2], [3], [4], [], [], [], [4], []]</p> <p><strong>Output:</strong> [null, true, true, true, false, 3, true, true, true, 4]</p> <p><strong>Explanation:</strong> 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</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= k <= 1000</code></li> <li><code>0 <= value <= 1000</code></li> <li>At most <code>3000</code> calls will be made to <code>enQueue</code>, <code>deQueue</code>, <code>Front</code>, <code>Rear</code>, <code>isEmpty</code>, and <code>isFull</code>.</li> </ul>

  • 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()