Example Interview Question

gistfile1.txt

// ==================
// Utility code start
// ==================

var Readable = require('stream').Readable;
var util = require('util');

/**
 * Stream which returns numbers in ascending sorted order.
 *
 * @param {Number} initialNum The first number
 * @param {Number} numbersInStream The total number of sorted numbers
 *                                 in the stream.
 * @constructor
 */
function SortedNumberStream(initialNum, numbersInStream) {
  this._count = 0;
  this._previousNum = initialNum;
  this._numbersInStream = numbersInStream;
  Readable.call(this, {objectMode: true});
};
util.inherits(SortedNumberStream, Readable);

/**
 * Generate the next number in the sorted sequence.
 *
 * @returns {null}
 * @private
 */
SortedNumberStream.prototype._read = function () {
  if (this._count === this._numbersInStream) {
    this.push(null);
  } else {
    this.push(this._previousNum);
    this._previousNum += randomIntFromInterval(0, 20);
    this._count++;
  }
};

SortedNumberStream.prototype.getStreamSize = function() {
  return this._numbersInStream;
}

/**
 * Utility function to generate a random number within a range.
 *
 * @param {Number} min The minimum number in the range, inclusive.
 * @param {Number} max The maximum number in the range, inclusive.
 * @returns {number}
 */
function randomIntFromInterval(min, max) {
  return Math.floor(Math.random() * (max - min + 1) + min);
}


// ====================
// Candidate code start
// ====================

var streams = [
  new SortedNumberStream(5, 10),
  new SortedNumberStream(19, 15),
  new SortedNumberStream(0, 7)
];



// A SortedNumberStream contains numbers in ascending order.
// Write an algoritm to sort the numbers in all of the streams
// and output them to a file, stdout, or another stream.