{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "true"
      ]
     },
     "execution_count": 1,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "load 'primes.rb'\n",
    "load 'array-numbers.rb'"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[1, 2, 3, 4]"
      ]
     },
     "execution_count": 13,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "1234.to_digits"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 53,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       ":valid"
      ]
     },
     "execution_count": 53,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "def valid(n, debug=false)\n",
    "  digits = n.to_digits\n",
    "  perms = digits.permutation.select {|ds| ds.to_i.prime?}.to_set.to_a.permutation(3)\n",
    "  puts \"perms: #{perms}\" if debug\n",
    "  triples = perms.to_a.map {|t| t.map {|ds| ds.to_i}}\n",
    "  puts \"triples: #{triples}\" if debug\n",
    "  valids = triples.select {|t| t[0] == n && t[1] > t[0] && t[1] - t[0] == t[2] - t[1]}\n",
    "  puts \"valids: #{valids}\" if debug\n",
    "  valids[0]\n",
    "end"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 35,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "false"
      ]
     },
     "execution_count": 35,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "valid(1234)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 56,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[148748178147, 296962999629]"
      ]
     },
     "execution_count": 56,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "(1000..9999).map {|n| valid n}.select {|t| !t.nil?}.map {|t| t.flat_map {|n| n.to_digits}.to_i}"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 57,
   "metadata": {
    "collapsed": false,
    "scrolled": true
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "perms: #<Enumerator:0x005594b994f0e0>\n",
      "triples: [[2969, 2699, 9629], [2969, 2699, 6299], [2969, 9629, 2699], [2969, 9629, 6299], [2969, 6299, 2699], [2969, 6299, 9629], [2699, 2969, 9629], [2699, 2969, 6299], [2699, 9629, 2969], [2699, 9629, 6299], [2699, 6299, 2969], [2699, 6299, 9629], [9629, 2969, 2699], [9629, 2969, 6299], [9629, 2699, 2969], [9629, 2699, 6299], [9629, 6299, 2969], [9629, 6299, 2699], [6299, 2969, 2699], [6299, 2969, 9629], [6299, 2699, 2969], [6299, 2699, 9629], [6299, 9629, 2969], [6299, 9629, 2699]]\n",
      "valids: [[2969, 6299, 9629]]\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "[2969, 6299, 9629]"
      ]
     },
     "execution_count": 57,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "valid(2969, debug=true)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  }
 ],
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