{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "true"
      ]
     },
     "execution_count": 1,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "require_relative 'array-numbers'"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 52,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "865"
      ]
     },
     "execution_count": 52,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "cubes = Hash.new {|h, k| h[k] = []}\n",
    "cube_roots = {}\n",
    "(100..1000).each do |i|\n",
    "  c = (i ** 3)\n",
    "  p = c.to_digits.sort.join\n",
    "  # cubes[p] = (cubes[p] + [c])\n",
    "  cubes[p] << c\n",
    "  cube_roots[c] = i\n",
    "end\n",
    "cubes.length"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 53,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "{\"01234566\"=>[41063625, 56623104, 66430125]}"
      ]
     },
     "execution_count": 53,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "cubes.select {|k, v| v.length >= 3}"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 42,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "345"
      ]
     },
     "execution_count": 42,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "cube_roots[41063625]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 58,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "127035954683"
      ]
     },
     "execution_count": 58,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "target = 5\n",
    "\n",
    "cubes = Hash.new {|h, k| h[k] = []}\n",
    "finished = false\n",
    "i = 100\n",
    "while ! finished\n",
    "  c = (i ** 3)\n",
    "  p = c.to_digits.sort.join\n",
    "  cubes[p] << c\n",
    "  if cubes[p].length == target\n",
    "    finished = true\n",
    "  else\n",
    "    i += 1\n",
    "  end\n",
    "end\n",
    "\n",
    "cubes[p].min"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Ruby 2.4.0",
   "language": "ruby",
   "name": "ruby"
  },
  "language_info": {
   "file_extension": ".rb",
   "mimetype": "application/x-ruby",
   "name": "ruby",
   "version": "2.4.0"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 2
}