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622_DesignCircularQueue.swift
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622_DesignCircularQueue.swift
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import Foundation
class MyCircularQueue {
/// 数组
private var items: [Int]
/// 数组最大长度
private let capacity: Int
/// 队头下标
private var head = -1
/// 队尾下标
private var tail = -1
private var size: Int = 0
/** Initialize your data structure here. Set the size of the queue to be k. */
init(_ k: Int) {
self.capacity = k
self.items = [Int](repeating: 0, count: capacity)
}
/** Insert an element into the circular queue. Return true if the operation is successful. */
func enQueue(_ value: Int) -> Bool {
if isFull() {
return false
}
tail = (tail + 1) % capacity
items[tail] = value
if size == 0 {
head = tail
}
size += 1
return true
}
/** Delete an element from the circular queue. Return true if the operation is successful. */
func deQueue() -> Bool {
if isEmpty() {
return false
}
head = (head + 1 ) % capacity
size -= 1
return true
}
/** Get the front item from the queue. */
func Front() -> Int {
return isEmpty() ? -1 : items[head]
}
/** Get the last item from the queue. */
func Rear() -> Int {
return isEmpty() ? -1 : items[tail]
}
/** Checks whether the circular queue is empty or not. */
func isEmpty() -> Bool {
return size == 0
}
/** Checks whether the circular queue is full or not. */
func isFull() -> Bool {
return size == capacity
}
}
/**
* Your MyCircularQueue object will be instantiated and called as such:
* let obj = MyCircularQueue(k)
* let ret_1: Bool = obj.enQueue(value)
* let ret_2: Bool = obj.deQueue()
* let ret_3: Int = obj.Front()
* let ret_4: Int = obj.Rear()
* let ret_5: Bool = obj.isEmpty()
* let ret_6: Bool = obj.isFull()
*/