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RingBufferQueue.swift
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RingBufferQueue.swift
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//
// RingBufferQueue.swift
// SwiftAlgorithm
//
// Created by Lee Myeonghwan on 2023/02/07.
//
import Foundation
struct RingBufferQueue<T>: CustomStringConvertible {
private var elements: [T?]
private var front = -1
private var rear = -1
init(count: Int) {
elements = Array(repeating: nil, count: count)
}
var isEmpty: Bool {
front == -1 && rear == -1
}
var isFull: Bool {
((rear + 1) % elements.count) == front
}
var description: String {
if isEmpty { return "Queue is empty..." }
return "---- Queue start ----\n"
+ elements.map({ String(describing: (String(describing: $0)))}).joined(separator: " -> ")
+ "\n---- Queue End ----\n"
}
var peek: T? {
if isEmpty { return nil }
return elements[front]
}
mutating func enqueue(_ element: T) -> Bool {
if isEmpty {
front = 0
rear = 0
elements[rear] = element
return true
}
if isFull {
print("Queue is Full")
return false
}
rear = (rear + 1) % elements.count
elements[rear] = element
return true
}
mutating func dequeue() -> T? {
if isEmpty {
print("Queue is empty")
return nil
}
if front == rear {
defer {
elements[front] = nil
front = -1
rear = -1
}
return elements[front]
}
defer {
elements[front] = nil
front = (front + 1) % elements.count
}
return elements[front]
}
}