Done puzzle 43

diff --git a/.gitignore b/.gitignore
index fabe9111243faf4cd38a18203168bef1d346553b..09d4d9aaeb3c4e7fe8ca42753902ccdbf5dbf7bd 100644 (file)
--- a/.gitignore
+++ b/.gitignore
@@ -61,3 +61,5 @@ build-iPhoneSimulator/
 # Profiling information
 profile.*
 
+# API secrets
+secrets.ini

diff --git a/euler43.ipynb b/euler43.ipynb
new file mode 100644 (file)
index 0000000..d11dcb5
--- /dev/null
+++ b/euler43.ipynb
@@ -0,0 +1,346 @@
+{
+ "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 'array-numbers.rb'"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "* d2d3d4=406 is divisible by 2\n",
+    "* d3d4d5=063 is divisible by 3\n",
+    "* d4d5d6=635 is divisible by 5\n",
+    "* d5d6d7=357 is divisible by 7\n",
+    "* d6d7d8=572 is divisible by 11\n",
+    "* d7d8d9=728 is divisible by 13\n",
+    "* d8d9d10=289 is divisible by 17"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       ":pluck"
+      ]
+     },
+     "execution_count": 2,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "def pluck(items)\n",
+    "  plucked = []\n",
+    "  items.each_index do |i|\n",
+    "    plucked << [items[i], items[0, i] + items[i+1..-1]]\n",
+    "  end\n",
+    "  plucked\n",
+    "end"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[[0, [1, 2, 3, 4]], [1, [0, 2, 3, 4]], [2, [0, 1, 3, 4]], [3, [0, 1, 2, 4]], [4, [0, 1, 2, 3]]]"
+      ]
+     },
+     "execution_count": 3,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "pluck([0,1,2,3,4])"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       ":choices"
+      ]
+     },
+     "execution_count": 4,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "def choices(partial_solution)\n",
+    "  choices = []\n",
+    "  pluck(partial_solution[:remaining]).each do |digit, remaining|\n",
+    "    choices << {digits: partial_solution[:digits] + [digit], remaining: remaining}\n",
+    "  end\n",
+    "  choices\n",
+    "end  "
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "{:digits=>[], :remaining=>[0, 1, 2, 3]}"
+      ]
+     },
+     "execution_count": 5,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "initial = {digits: [], remaining: (0..3).to_a}"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 6,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[{:digits=>[0], :remaining=>[1, 2, 3]}, {:digits=>[1], :remaining=>[0, 2, 3]}, {:digits=>[2], :remaining=>[0, 1, 3]}, {:digits=>[3], :remaining=>[0, 1, 2]}]"
+      ]
+     },
+     "execution_count": 6,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "choices(initial)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[{:digits=>[0, 1], :remaining=>[2, 3]}, {:digits=>[0, 2], :remaining=>[1, 3]}, {:digits=>[0, 3], :remaining=>[1, 2]}, {:digits=>[1, 0], :remaining=>[2, 3]}, {:digits=>[1, 2], :remaining=>[0, 3]}, {:digits=>[1, 3], :remaining=>[0, 2]}, {:digits=>[2, 0], :remaining=>[1, 3]}, {:digits=>[2, 1], :remaining=>[0, 3]}, {:digits=>[2, 3], :remaining=>[0, 1]}, {:digits=>[3, 0], :remaining=>[1, 2]}, {:digits=>[3, 1], :remaining=>[0, 2]}, {:digits=>[3, 2], :remaining=>[0, 1]}]"
+      ]
+     },
+     "execution_count": 7,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "choices(initial).flat_map {|s| choices(s)}"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 8,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       ":solve0"
+      ]
+     },
+     "execution_count": 8,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "def solve0()\n",
+    "  initial = {digits: [], remaining: (0..9).to_a}\n",
+    "  d0s = choices(initial)\n",
+    "  d1s = d0s.flat_map {|s| choices(s)}\n",
+    "  d2s = d1s.flat_map {|s| choices(s)}\n",
+    "  d3s = d2s.flat_map {|s| choices(s)}.select {|s| s[:digits][-3..-1].to_i % 2 == 0}\n",
+    "  d4s = d3s.flat_map {|s| choices(s)}.select {|s| s[:digits][-3..-1].to_i % 3 == 0}\n",
+    "  d5s = d4s.flat_map {|s| choices(s)}.select {|s| s[:digits][-3..-1].to_i % 5 == 0}\n",
+    "  d6s = d5s.flat_map {|s| choices(s)}.select {|s| s[:digits][-3..-1].to_i % 7 == 0}\n",
+    "  d7s = d6s.flat_map {|s| choices(s)}.select {|s| s[:digits][-3..-1].to_i % 11 == 0}\n",
+    "  d8s = d7s.flat_map {|s| choices(s)}.select {|s| s[:digits][-3..-1].to_i % 13 == 0}\n",
+    "  d9s = d8s.flat_map {|s| choices(s)}.select {|s| s[:digits][-3..-1].to_i % 17 == 0}\n",
+    "  # puts \"0: #{d0s.length}, 1: #{d1s.length}, 2: #{d2s.length}, 3: #{d3s.length}, 4: #{d4s.length}, 5: #{d5s.length}, 6: #{d6s.length}, 7: #{d7s.length}, 8: #{d8s.length}, 9: #{d9s.length}\"\n",
+    "  d9s.map {|s| s[:digits].to_i}.sum\n",
+    "end"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       ":solve_step"
+      ]
+     },
+     "execution_count": 9,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "def solve_step(partial_solutions, divisor)\n",
+    "  solns = partial_solutions.flat_map {|s| choices(s)}\n",
+    "  if divisor == 1\n",
+    "    solns\n",
+    "  else\n",
+    "    solns.select {|s| s[:digits][-3..-1].to_i % divisor == 0}\n",
+    "  end\n",
+    "end"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 10,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       ":solve"
+      ]
+     },
+     "execution_count": 10,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "def solve()\n",
+    "  initial = {digits: [], remaining: (0..9).to_a}\n",
+    "  solutions = choices(initial)\n",
+    "  [1, 1, 2, 3, 5, 7, 11, 13, 17].each do |d|\n",
+    "    # puts \"#{d}, #{solutions.length}, #{solutions[0][:digits].length}\"\n",
+    "    solutions = solve_step(solutions, d)\n",
+    "  end\n",
+    "  solutions.map {|s| s[:digits].to_i}.sum\n",
+    "end"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 11,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "16695334890"
+      ]
+     },
+     "execution_count": 11,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "solve0"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 12,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "16695334890"
+      ]
+     },
+     "execution_count": 12,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "solve"
+   ]
+  },
+  {
+   "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
+}