[백준 18258] 큐 2 with Node.js

문제 링크

www.acmicpc.net/problem/18258

18258번: 큐 2

풀이

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

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

    createNode(value, prev, next) {
        return {
            value,
            prev,
            next
        };
    }

    push(value) {
        const curNode = this.createNode(value, this.tail, this.head);
        if (this.head) {
            this.tail.next = curNode;
            this.head.prev = curNode;
            this.tail = curNode;
        } else {
            this.head = curNode;
            this.tail = curNode;
            curNode.prev = curNode;
            curNode.next = curNode;
        }
        this.size++;
    }

    pop() {
        if (this.size > 2) {
            const value = this.head.value;
            const newHead = this.head.next;
            this.head = newHead;
            newHead.prev = this.tail;
            this.tail.next = this.head;
            this.size--;
            return value;
        } else if (this.size === 2) {
            const value = this.head.value;
            this.head = this.tail;
            this.tail.prev = this.tail;
            this.tail.next = this.tail;
            this.size--;
            return value;
        } else if (this.size === 1) {
            const value = this.head.value;
            this.head = null;
            this.tail = null;
            this.size--;
            return value;
        } else {
            return -1;
        }
    }

    empty() {
        return this.size ? 0 : 1;
    }

    front() {
        return this.head ? this.head.value : -1;
    }

    back() {
        return this.tail ? this.tail.value : -1;
    }
}

const myQueue = new Queue();
const output = [];

for (let i=1; i<input.length; i++) {
    const [command, value] = input[i].split(" ");
    switch(command) {
        case "push": myQueue.push(value); break;
        case "pop": output.push(myQueue.pop()); break;
        case "size": output.push(myQueue.size); break;
        case "empty": output.push(myQueue.empty()); break;
        case "front": output.push(myQueue.front()); break;
        case "back": output.push(myQueue.back()); break;
    }
}
console.log(output.join("\n"));

Queue 클래스를 구현하여 해결하였다.