{
 "metadata": {
  "name": ""
 },
 "nbformat": 3,
 "nbformat_minor": 0,
 "worksheets": [
  {
   "cells": [
    {
     "cell_type": "markdown",
     "source": [
      "If the numbers 1 to 5 are written out in words: one, two, three, four, five, then there are 3 + 3 + 5 + 4 + 4 = 19 letters used in total.\n",
      "\n",
      "If all the numbers from 1 to 1000 (one thousand) inclusive were written out in words, how many letters would be used?\n",
      "\n",
      "NOTE: Do not count spaces or hyphens. For example, 342 (three hundred and forty-two) contains 23 letters and 115 (one hundred and fifteen) contains 20 letters. The use of \"and\" when writing out numbers is in compliance with British usage."
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "  def pro_one(num) # 1..19\n",
      "    return \"\" if num == 0\n",
      "    %w(zero one two three four five six seven eight nine ten eleven twelve thirteen fourteen fifteen sixteen seventeen eighteen nineteen)[num]\n",
      "  end\n",
      "  \n",
      "  pro_one(5)"
     ],
     "language": "python",
     "outputs": [
      {
       "output_type": "pyout",
       "prompt_number": 3,
       "text": [
        "\"five\""
       ]
      }
     ],
     "prompt_number": 3
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "  def pro_ten(num) # 20..99\n",
      "    return pro_one(num) if num < 20\n",
      "    tens = %w(zero ten twenty thirty forty fifty sixty seventy eighty ninety)\n",
      "    \n",
      "    ten, one = num.to_s.split(\"\").map{|i|i.to_i}\n",
      "    return tens[ten] + \" \" + pro_one(one)\n",
      "  end\n",
      "  \n",
      "  pro_ten(56)"
     ],
     "language": "python",
     "outputs": [
      {
       "output_type": "pyout",
       "prompt_number": 4,
       "text": [
        "\"fifty six\""
       ]
      }
     ],
     "prompt_number": 4
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "def pro_hundred(num) #100..999\n",
      "  return pro_ten(num) if num < 100\n",
      "  return \"one thousand\" if num == 1000\n",
      "  hun, ten_one = [num.to_s[0].to_i, num.to_s[1..2].to_i]\n",
      "  return pro_one(hun) + \" hundred and \" + pro_ten(ten_one) if ten_one != 0\n",
      "  return pro_one(hun) + \" hundred\"\n",
      "end\n",
      "\n",
      "pro_hundred(430)"
     ],
     "language": "python",
     "outputs": [
      {
       "output_type": "pyout",
       "prompt_number": 5,
       "text": [
        "\"four hundred and thirty \""
       ]
      }
     ],
     "prompt_number": 5
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "(1..1000).to_a.map{|i| pro_hundred(i).gsub(/[ \\-]/, \"\").length }.inject &:+"
     ],
     "language": "python",
     "outputs": [
      {
       "output_type": "pyout",
       "prompt_number": 6,
       "text": [
        "21124"
       ]
      }
     ],
     "prompt_number": 6
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "pro_hundred(115).gsub(/[ \\-]/, \"\").length"
     ],
     "language": "python",
     "outputs": [
      {
       "output_type": "pyout",
       "prompt_number": 7,
       "text": [
        "20"
       ]
      }
     ],
     "prompt_number": 7
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [],
     "language": "python",
     "outputs": []
    }
   ]
  }
 ]
}