Project-Euler Helpers

About

Collection of JS helper functions for commonly occuring tasks in the Project-Euler problem set.

Setup

npm i --save project-euler-helpers

Usage

Array prototype methods are available wherever this package is imported:

• Array.unique()
• Array.last()

Import your desired methods from 'project-euler-helpers':

• runtime(func, args)
• isFib(num)
• genFibArr(length)
• fibNthTerm(n)
• nextFib(last, secondLast)
• isPrime(num)
• genPrimeArr(length)
• genPrimeArrUnderMax(max)
• findFactors(num)
• findFactorCount(num)
• findFactorSum(num)
• isPalindrome(num/str)
• isPandigital(num, max)
• genGrid(rows, cols, fill)
• genAlphaArr(charStart, charEnd)
• genAlphaObj(charStart, charEnd)
• triangle(num)
• isTriangle(num)
• pentagonal(num)
• isPentagonal(num)
• hexagonal(num)
• isHexagonal(num)

Examples:

require('project-euler-helpers')

// your arr
let arr = [1, 4, 2, 1, 2, 7]

arr.last() // 7

// this will sort your num array... do not use if index matters
arr.unique() // [1, 2, 4, 7]

const { runtime } = require('project-euler-helpers')

// your function
const func = (argument1, argument2, ...) => value

runtime(func, argument1, argument2) 
/*
* func returned: value
* runtime: 0.0s
*/

const { genFibArr, fibNthTerm, isFib } = require('project-euler-helpers')

genFibArr(10) // [ 1, 1, 2, 3, 5, 8, 13, 21, 34, 55 ]
fibNthTerm(10) // 55
nextFib([1, 3], [8]) // [2, 1] -> for use with big nums, takes/returns array of digits
isFib(55) // true
isFib(4) // false

const { isPrime, genPrimeArr, genPrimeArrUnderMax } = require('project-euler-helpers')

genPrimeArr(5) // [2, 3, 5, 7, 11]
genPrimeArrUnderMax(11) // [2, 3, 5, 7]
isPrime(11) // true
isPrime(10) // false

const { findFactors, findFactorSum, findFactorCount } = require('project-euler-helpers')

findFactors(10) // [1, 2, 5, 10] *unsorted*
findFactorSum(10) // 18
findFactorCount(10) // 4

const { isPalindrome } = require('project-euler-helpers')

isPalindrome(101) // true
isPalindrome('101') // true
isPalindrome(1010) // false

const { genGrid } = require('project-euler-helpers')

genGrid(3, 4, 0) // [[0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0]]

const { isPandigital } = require('project-euler-helpers')

// second arg is range(1, max) inclusive
isPandigital(123456789) // true
isPandigital(53142, 5) // true
isPandigital(12345, 4) // false

const { genAlphaArr, genAlphaObj } = require('project-euler-helpers')

genAlphaArr('A', 'Z') // ['A', 'B', ... ,'Z']
genAlphaObj('a', 'x') // { 'a': 1, 'b': 2, ..., 'z': 26}

const { 
  triangle, isTriangle, pentagonal, isPentagonal, hexagonal, isHexagonal 
} = require('project-euler-helpers')

isTriangle(triangle(10)) // true
isPentagonal(pentagonal(10)) // true
isHexagonal(hexagonal(10)) // true