LeetCode in Kotlin

641. Design Circular Deque

Medium

Design your implementation of the circular double-ended queue (deque).

Implement the MyCircularDeque class:

• MyCircularDeque(int k) Initializes the deque with a maximum size of k.
• boolean insertFront() Adds an item at the front of Deque. Returns true if the operation is successful, or false otherwise.
• boolean insertLast() Adds an item at the rear of Deque. Returns true if the operation is successful, or false otherwise.
• boolean deleteFront() Deletes an item from the front of Deque. Returns true if the operation is successful, or false otherwise.
• boolean deleteLast() Deletes an item from the rear of Deque. Returns true if the operation is successful, or false otherwise.
• int getFront() Returns the front item from the Deque. Returns -1 if the deque is empty.
• int getRear() Returns the last item from Deque. Returns -1 if the deque is empty.
• boolean isEmpty() Returns true if the deque is empty, or false otherwise.
• boolean isFull() Returns true if the deque is full, or false otherwise.

Example 1:

Input

[“MyCircularDeque”, “insertLast”, “insertLast”, “insertFront”, “insertFront”, “getRear”, “isFull”, “deleteLast”, “insertFront”, “getFront”]

[[3], [1], [2], [3], [4], [], [], [], [4], []]

Output: [null, true, true, true, false, 2, true, true, true, 4]

Explanation:

MyCircularDeque myCircularDeque = new MyCircularDeque(3);

myCircularDeque.insertLast(1); // return True

myCircularDeque.insertLast(2); // return True

myCircularDeque.insertFront(3); // return True

myCircularDeque.insertFront(4); // return False, the queue is full.

myCircularDeque.getRear(); // return 2

myCircularDeque.isFull(); // return True

myCircularDeque.deleteLast(); // return True

myCircularDeque.insertFront(4); // return True

myCircularDeque.getFront(); // return 4

Constraints:

• 1 <= k <= 1000
• 0 <= value <= 1000
• At most 2000 calls will be made to insertFront, insertLast, deleteFront, deleteLast, getFront, getRear, isEmpty, isFull.

Solution

@Suppress("kotlin:S6512")
class MyCircularDeque(k: Int) {
    private val data: IntArray
    private var front: Int
    private var rear: Int
    private var size: Int

    init {
        data = IntArray(k)
        front = 0
        rear = k - 1
        size = 0
    }

    fun insertFront(value: Int): Boolean {
        if (size == data.size) {
            return false
        }
        data[front] = value
        front = (front + 1) % data.size
        size++
        return true
    }

    fun insertLast(value: Int): Boolean {
        if (size == data.size) {
            return false
        }
        data[rear] = value
        rear = (rear - 1 + data.size) % data.size
        size++
        return true
    }

    fun deleteFront(): Boolean {
        if (size == 0) {
            return false
        }
        front = (front - 1 + data.size) % data.size
        size--
        return true
    }

    fun deleteLast(): Boolean {
        if (size == 0) {
            return false
        }
        rear = (rear + 1) % data.size
        size--
        return true
    }

    fun getFront(): Int {
        return if (size == 0) {
            -1
        } else data[(front - 1 + data.size) % data.size]
    }

    fun getRear(): Int {
        return if (size == 0) {
            -1
        } else data[(rear + 1) % data.size]
    }

    fun isEmpty(): Boolean {
        return size == 0
    }
    fun isFull(): Boolean {
        return size == data.size
    }
}

/*
 * Your MyCircularDeque object will be instantiated and called as such:
 * var obj = MyCircularDeque(k)
 * var param_1 = obj.insertFront(value)
 * var param_2 = obj.insertLast(value)
 * var param_3 = obj.deleteFront()
 * var param_4 = obj.deleteLast()
 * var param_5 = obj.getFront()
 * var param_6 = obj.getRear()
 * var param_7 = obj.isEmpty()
 * var param_8 = obj.isFull()
 */

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