Node.js) 백준 3078번: 좋은 친구

https://www.acmicpc.net/problem/3078

3078번: 좋은 친구

 

class Node {
	constructor(item) {
		this.item = item;
		this.next = null;
	}
}

class Queue {
	constructor() {
		this.head = null;
		this.tail = null;
		this.length = 0;
	}

	push(item) {
		const node = new Node(item);
		if (this.head == null) {
			this.head = node;
		} else {
			this.tail.next = node;
		}

		this.tail = node;
		this.length += 1;
	}

	pop() {
		const popItem = this.head;
		this.head = this.head.next;
		this.length -= 1;
		return popItem.item;
	}
}

const input = require('fs').readFileSync('./dev/stdin').toString().trim().split('\n');

const [N, K] = input.shift().split(' ').map(Number);

const q = Array.from(Array(21), () => new Queue());

let answer = 0;

input.forEach((v, i) => {
	const Len = v.trim().length;
	while (q[Len].length > 0 && i - q[Len].head.item > K) q[Len].pop();
	answer += q[Len].length;
	q[Len].push(i);
});

console.log(answer);