package LeetCode_622
/**
* 622. Design Circular Queue
* https://leetcode.com/problems/design-circular-queue/description/
*
* Your implementation should support following operations:
MyCircularQueue(k): Constructor, set the size of the queue to be k.
Front: Get the front item from the queue. If the queue is empty, return -1.
Rear: Get the last item from the queue. If the queue is empty, return -1.
enQueue(value): Insert an element into the circular queue. Return true if the operation is successful.
deQueue(): Delete an element from the circular queue. Return true if the operation is successful.
isEmpty(): Checks whether the circular queue is empty or not.
isFull(): Checks whether the circular queue is full or not.
* */
class MyCircularQueue(k: Int) {
var array: IntArray? = null
var size = 0
var currentSize = 0
var front = -1
//rear always pointed to the available location where can insert new data
var rear = -1
/** Initialize your data structure here. Set the size of the queue to be k. */
init {
this.size = k
array = IntArray(size)
}
/** Insert an element into the circular queue. Return true if the operation is successful. */
fun enQueue(value: Int): Boolean {
if (isFull()) {
return false
}
rear = (rear + 1) % size //for example: 2%5=2, -2%5=-2, 2%-5=2
array!![rear] = value
currentSize++
if (front == -1) {
front = rear
}
return true
}
/** Delete an element from the circular queue. Return true if the operation is successful. */
fun deQueue(): Boolean {
if (isEmpty()) {
return false
}
//move the front to next
//val deQeueuElement = array!![front]
front = (front + 1) % size
currentSize--
return true
}
/** Get the front item from the queue. */
fun Front(): Int {
return if (isEmpty()) -1 else array!![front]
}
/** Get the last item from the queue. */
fun Rear(): Int {
return if (isEmpty()) -1 else array!![rear]
}
/** Checks whether the circular queue is empty or not. */
fun isEmpty(): Boolean {
return currentSize == 0
}
/** Checks whether the circular queue is full or not. */
fun isFull(): Boolean {
return currentSize == array?.size
}
}
/**
* Your MyCircularQueue object will be instantiated and called as such:
* var obj = MyCircularQueue(k)
* var param_1 = obj.enQueue(value)
* var param_2 = obj.deQueue()
* var param_3 = obj.Front()
* var param_4 = obj.Rear()
* var param_5 = obj.isEmpty()
* var param_6 = obj.isFull()
*/
