baekjoon. 큐 2

문제

문제 링크

풀이

말 그대로 큐를 구현하면 되는 문제

코드

    const input = `15
push 1
push 2
front
back
size
empty
pop
pop
pop
size
empty
pop
push 3
empty
front`.split('\n').map(v=>v.split(' ')).slice(1);

    // const input = require("fs").readFileSync("/dev/stdin").toString().trim().split('\n').map(v=>v.split(' ')).slice(1);


    class Node {
        constructor(number, prev=null, next=null) {
            this.number = number;
            this.prev = prev;
            this.next = next;
        }
    }
    class Queue{
        constructor(head, tail) {
            this.head = null;
            this.tail = null;
            this.length = 0;
        }
        push(number){
            const newNode = new Node(Number(number));
            if(this.length===0) {
                this.head = newNode;
                this.tail = newNode;
            }else {
                this.tail.next = newNode;
                this.tail = newNode;
            }
            this.length++;
        }

        pop(){
            if(this.length === 0) {
                answer += -1 + '\n';
                return;
            }
            const temp = this.head.number;
            this.head = this.head.next;
            this.length--;
            if(this.length===0) {
                this.tail = null;
            }
            answer += temp +'\n';
        }

        size(){
            answer += this.length +'\n';
        }

        empty(){
            answer += (this.length ? 0 : 1) +'\n';
        }

        front(){
            answer += (this.head ? this.head.number : -1) +'\n';
        }

        back(){
            answer += (this.tail ? this.tail.number : -1) +'\n';
        }
    }
    const queue = new Queue();
    let answer = '';

    for (let i=0; i<input.length;i++){
        const [order,number] = input[i];

        queue[order](number);
    }

    console.log(answer);