Queue Optimised 이전과 달리 items를 객체{}로 선언해주었다. class Queue { constructor() { this.items = {} this.rear = 0 this.front = 0 } enqueue(element) { this.items[this.rear] = element this.rear++ } dequeue() { const item = this.items[this.front] delete this.items[this.front] this.front++ return item } isEmpty() { return this.rear - this.front === 0 } peek() { return this.items[this.front] } size() { return ..