Design a queue using linked list

Question

Design a queue using linked list Given the skeleton of a Queue class, complete this class by implementing all the queue operations below. > - **Queue(int capacity)** - Initializes the Queue object with the given capacity. > - **size()** - Returns the current size of the queue. > - **empty()** - Returns `true` if the queue is empty and `false` if not. > - **front()** - Returns the element at the front of the queue. If the queue is empty, it returns `-1`. > - **back()** - Returns the element at the back of the queue. If the queue is empty, it returns `-1`. > - **enqueue(int val)** - Adds the given value to the queue and returns `true` if the operation is successful. Returns `false` if the queue is full. > - **dequeue()** - Removes the front element from the queue and returns its value. If the queue is empty, it returns `-1`. You must abide by the following constraints > The input should adhere to the following rules: > 1. The input should contain two arrays of the same size. > 2. The first array should contain the list of operations, while the second should contain the corresponding operands for those operations. > 3. The first index in the first array should contain **Queue**, and the first index in the second array should contain a single positive integer representing the capacity of the queue. This value is used to initialise the queue. > 4. For each index in the first array that contains the **enqueue** operation, the corresponding index in the second array should contain the value that needs to be pushed. > 5. For each index in the first array that contains **size**, **empty**, **front**, **back**, or **dequeue** operations, the corresponding index in the second array should contain an empty array. > > **Example:** > - **Input:** [Queue, enqueue, back, enqueue, front, empty, dequeue, front, enqueue, enqueue, empty] [[2], [2], [], [3], [], [], [], [], [8], [9], []] > > - **Output:** [null, true, 2, true, 2, false, 2, 3, true, false, false] > > **Explanation:** > > **Operation:** Queue queue = new Queue(2) > **Result:** Initializes an empty `Queue` with a capacity of 2 > > **Operation:** queue.enqueue(2) > **Result:** `queue = [2]`, returns `true` > > **Operation:** queue.back() > **Result:** `queue = [2]`, returns `2` > > **Operation:** queue.enqueue(3) > **Result:** `queue = [2, 3]`, returns `true` > > **Operation:** queue.front() > **Result:** `queue = [2, 3]`, returns `2` > > **Operation:** queue.empty() > **Result:** `queue = [2, 3]`, returns `false` > > **Operation:** queue.dequeue() > **Result:** `queue = [3]`, returns `2` > > **Operation:** queue.front() > **Result:** `queue = [3]`, returns `3` > > **Operation:** queue.enqueue(8) > **Result:** `queue = [3, 8]`, returns `true` > > **Operation:** queue.enqueue(9) > **Result:** `queue = [3, 8]`, queue is full, returns `false` > > **Operation:** queue.empty() > **Result:** `queue = [3, 8]`, returns `false`

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Optimal Solution: Time Complexity All operations in O(1), Space Complexity O(1). Codeintuition provides an interactive coding environment for this problem.

Queue

Introduction to queues

Array implementation of queues

Linked list implementation of queues

Design

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