알고리즘 기초 - 3 (Data Structure)

queue

class Queue {
  constructor() {
    this.data = [];
  }
  add(record) {
    this.data.unshift(record);
  }
  remove(record) {
    return this.data.pop();
  }
  peek() {
    return this.data[this.data.length - 1];
  }
}

weave

const Queue = require('./queue');

function weave(sourceOne, sourceTwo) {
  const q = new Queue();
  while (sourceOne.peek() || sourceTwo.peek()) {
    if (sourceOne.peek()) {
      q.add(sourceOne.remove());
    }

    if (sourceTwo.peek()) {
      q.add(sourceTwo.remove());
    }
  }
  return q;
}

stack

class Stack {
  constructor() {
    this.data = [];
  }
  push(record) {
    this.data.push(record);
  }
  pop() {
    return this.data.pop();
  }
  peek() {
    return this.data[this.data.length - 1];
  }
}

qfroms (queue from stack) - queue 2개로 stack 만들기

const Stack = require('./stack');

class Queue {
  constructor() {
    this.first = new Stack();
    this.second = new Stack();
  }

  add(record) {
    this.first.push(record);
  }

  remove() {
    while (this.first.peek()) {
      this.second.push(this.first.pop());
    }
    const record = this.second.pop();
    while (this.second.peek()) {
      this.first.push(this.second.pop());
    }
    return record;
  }

  peek() {
    while (this.first.peek()) {
      this.second.push(this.first.pop());
    }

    const record = this.second.peek();
    while (this.second.peek()) {
      this.first.push(this.second.pop());
    }
    return record;
  }
}