기본 자료구조

class Que {
    constructor() {
        this._arr = []
    }
    enqueue(item) {
        this._arr.push(item)
    }
    dequeue() {
        return this._arr.shift()
    }
}

class Stack {
    constructor() {
        this._arr = []
    }
    push(item) {
        this._arr.push()
    }
    pop() {
        this.pop()
    }
    peak() {
        return this._arr[this._arr.length - 1]
    }
}

class Node {
    constructor(content, children = []) {
        this.content = content
        this.children = children
    }
}