Done puzzle 49

diff --git a/euler49.ipynb b/euler49.ipynb
new file mode 100644 (file)
index 0000000..b9cf0a6
--- /dev/null
+++ b/euler49.ipynb
@@ -0,0 +1,180 @@
+{
+ "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": []
+  }
+ ],
+ "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": 0
+}