class Node {
constructor(value) {
this.value = value;
this.next = null;
}
}
class Queue {
constructor() {
this.first = null;
this.last = null;
this.length = 0;
}
peek() {
return this.first;
}
enqueue(value) {
// @ -> @ -> @ -> null
const newNode = new Node(value);
if (this.length === 0) {
this.first = newNode;
this.last = newNode;
console.log(this);
} else {
this.last.next = newNode;
this.last = newNode;
}
this.length++;
return this;
}
dequeue() {
if (!this.first) {
return null;
}
if (this.first === this.last) {
this.last = null;
}
this.first = this.first.next;
this.length--;
return this;
}
}
const queue = new Queue();
queue.enqueue(10);
queue.enqueue(11);
queue.enqueue(12);
queue.enqueue(13);
queue.enqueue(14);
console.log(queue.enqueue(20));
console.log(queue.dequeue());
