Node.js) 백준 4949번 : 균형 잡힌 세상

https://www.acmicpc.net/problem/4949

4949번: 균형잡힌 세상

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

command.pop();
class Node{
    constructor(item){
      this.item = item;
      this.next = null;
    }
  }
  
  class Stack{
    constructor(){
      this.topOfStack = null;
      this.length = 0;
    }
  
    push(item){
      const node = new Node(item);
      if(this.topOfStack!=null){
        node.next = this.topOfStack; 
      }
        this.topOfStack = node;
        this.length+=1;
    }
  
    pop(){
      if(this.length==0)return -1;
      const popItem = this.topOfStack;
      this.topOfStack = popItem.next;
      this.length-=1;

      return popItem.item
    }
  
    size(){
      return this.length;
    }
  
    empty(){
      if(this.length==0) return 1;
      else return 0;
    }
  
    top(){
      if(this.length==0)return -1;
      return this.topOfStack.item; 
    }
  
  }


let answer = [];

command.forEach(v=>{
    let stack = new Stack(); 
    for(let i = 0; i<v.length; i++){
        if(v[i]=='(' || v[i]==')' ||v[i]=='[' ||v[i]==']' ){
            if(stack.empty()==1){
                stack.push(v[i])
            }else if(stack.top()=='(' && v[i]==')'){
                stack.pop();
            }else if(stack.top()=='[' && v[i]==']'){
                stack.pop();
            }
            else{
                stack.push(v[i]);
            }
        }
    }
    if(stack.empty()==1) answer.push('yes')
    else answer.push('no')
})

console.log(answer.join('\n'));