Design Circular Queue LeetCode Solution

Problem – Design Circular Queue

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 enQueuedeQueueFrontRearisEmpty, and isFull.

Design Circular Queue LeetCode Solution in Python

class MyCircularQueue:
    def __init__(self, k: int):
        self.data = [0] * k
        self.maxSize = k
        self.head = 0
        self.tail = -1
    def enQueue(self, val: int) -> bool:
        if self.isFull(): return False
        self.tail = (self.tail + 1) % self.maxSize
        self.data[self.tail] = val
        return True
    def deQueue(self) -> bool:
        if self.isEmpty(): return False
        if self.head == self.tail: self.head, self.tail = 0, -1
        else: self.head = (self.head + 1) % self.maxSize
        return True
    def Front(self) -> int:
        return -1 if self.isEmpty() else self.data[self.head]
    def Rear(self) -> int:
        return -1 if self.isEmpty() else self.data[self.tail]
    def isEmpty(self) -> bool:
        return self.tail == -1
    def isFull(self) -> bool:
        return not self.isEmpty() and (self.tail + 1) % self.maxSize == self.head

Design Circular Queue LeetCode Solution in Java

class MyCircularQueue {
    int maxSize, head = 0, tail = -1;
    int[] data;
    public MyCircularQueue(int k) {
        data = new int[k];
        maxSize = k;
    }
    public boolean enQueue(int val) {
        if (isFull()) return false;
        tail = (tail + 1) % maxSize;
        data[tail] = val;
        return true;
    }
    public boolean deQueue() {
        if (isEmpty()) return false;
        if (head == tail) {
            head = 0;
            tail = -1;
        } else head = (head + 1) % maxSize;
        return true;
    }
    public int Front() {
        return isEmpty() ? -1 : data[head];
    }
    public int Rear() {
        return isEmpty() ? -1 : data[tail];
    }
    public boolean isEmpty() {
        return tail == -1;
    }
    public boolean isFull() {
        return !isEmpty() && (tail + 1) % maxSize == head;
    }

Design Circular Queue LeetCode Solution in C++

class MyCircularQueue {
public:
    MyCircularQueue(int k) {
        data.resize(k);
        maxSize = k;
    }
    bool enQueue(int val) {
        if (isFull()) return false;
        tail = (tail + 1) % maxSize;
        data[tail] = val;
        return true;
    }
    bool deQueue() {
        if (isEmpty()) return false;
        if (head == tail) head = 0, tail = -1;
        else head = (head + 1) % maxSize;
        return true;
    }
    int Front() {
        return isEmpty() ? -1 : data[head];
    }
    int Rear() {
        return isEmpty() ? -1 : data[tail];
    }
    bool isEmpty() {
        return tail == -1;
    }
    bool isFull() {
        return !isEmpty() && (tail + 1) % maxSize == head;
    }
private:
    int maxSize, head = 0, tail = -1;
    vector<int> data;
};
Design Circular Queue LeetCode Solution Review:

In our experience, we suggest you solve this Design Circular Queue LeetCode Solution and gain some new skills from Professionals completely free and we assure you will be worth it.

If you are stuck anywhere between any coding problem, just visit Queslers to get the Design Circular Queue LeetCode Solution

Find on LeetCode

Conclusion:

I hope this Design Circular Queue LeetCode Solution would be useful for you to learn something new from this problem. If it helped you then don’t forget to bookmark our site for more Coding Solutions.

This Problem is intended for audiences of all experiences who are interested in learning about Data Science in a business context; there are no prerequisites.

Keep Learning!

More Coding Solutions >>

LeetCode Solutions

Hacker Rank Solutions

CodeChef Solutions

Leave a Reply

Your email address will not be published.