백준 10828 스택 (자료구조)

문제

제한 사항

입출력 예

풀이

class Stack {
  constructor() {
    this.arr = [];
  }
  size() {
    return this.arr.length;
  }
  push(item) {
    this.arr.push(item);
    //this.arr[this.arr.length] = item;
  }
  pop() {
    if (this.arr.length <= 0) return -1;
    const result = this.arr.pop();
    return result;
  }
  top() {
    if (this.arr.length <= 0) {
      return -1;
    }
    return this.arr[this.arr.length - 1];
  }
  isEmpty() {
    if (!this.arr.length) {
      return true;
    }
    return false;
  }
}
const input = require('fs').readFileSync('/dev/stdin').toString().trim().split('\n');
const N = +input.shift();
const myStack = new Stack();
let answer = "";
input.forEach((e, i) => {
  const [cmd, item] = e.split(" ");
  if (cmd === "push") {
    myStack.push(item);
  } else if (cmd === "top") {
    answer += myStack.top() + "\n";
  } else if (cmd === "size") {
    answer += myStack.size() + "\n";
  } else if (cmd === "pop") {
    answer += myStack.pop() + "\n";
  } else {
    if (myStack.isEmpty()) {
      answer += 1 + "\n";
    } else {
      answer += 0 + "\n";
    }
  }
});

console.log(answer.trim());

• class로 stack을 구현했다.