mathball/lib/hoax/index.js

A JavaScript library for Competitive Programming

'use strict';

var validate = require('../validation/positive-integer');
var check = require('../check');
/**
 * hoax Number
 */

/**
 * find distinct prime factors
 */
var findPrimeFactors = function findPrimeFactors(num) {
  var primeFactorArr = [];

  if (num % 2 === 0) {
    while (num % 2 === 0) {
      num /= 2;
    }
    primeFactorArr.push(2);
  }

  for (var i = 3; i <= Math.sqrt(num); i += 2) {
    // Check if i is prime factor
    if (num % i === 0) {
      while (num % i === 0) {
        num /= i;
      }
      primeFactorArr.push(i);
    }
  }

  if (num > 2) {
    primeFactorArr.push(num);
  }
  return primeFactorArr;
};

/**
 * check if the number is a hoax
 */
var isHoaxNumber = function isHoaxNumber(num) {

  if (check('prime')(num) === true) {
    return false;
  } else {
    num = num.toString();
    var primeFactor = findPrimeFactors(num);
    var sumofNum = num.split('').map(function (val) {
      return Number(val);
    }).reduce(function (a, b) {
      return a + b;
    });

    var sumOfPrimeFactor = 0;
    for (var i = 0; i < primeFactor.length; i++) {
      var sum = 0;
      var pf = primeFactor[i];
      while (pf > 0) {
        sum += pf % 10;
        pf = parseInt(pf / 10, 10);
      }
      sumOfPrimeFactor += sum;
    }

    return sumofNum === sumOfPrimeFactor;
  }
};

exports.check = function (num) {
  validate(num);
  return isHoaxNumber(num);
};