Merge ed17497 into 98faaf9

Makefile

@@ -11,16 +11,14 @@ install:
 
 solve:
 	./towers console --discs $(or $(discs),3)
-
+
+solve-constrained:
+		./towers console --discs $(or $(discs),3) --constrained
+
 phat:
 	python webserver.py &
 	sleep 2
-	./towers phat
-
-fake-phat:
-	python dummywebserver.py &
-	sleep 2
-	./towers phat
+	./towers phat --constrained
 
 kill:
 	kill `ps ax | grep webser | tr -s ' ' ' ' | cut -d ' ' -f 1`

README.md

@@ -40,3 +40,29 @@ make phat
 to watch this all play out on the pHAT:
 
 <blockquote class="instagram-media" data-instgrm-version="7" style=" background:#FFF; border:0; border-radius:3px; box-shadow:0 0 1px 0 rgba(0,0,0,0.5),0 1px 10px 0 rgba(0,0,0,0.15); margin: 1px; max-width:658px; padding:0; width:99.375%; width:-webkit-calc(100% - 2px); width:calc(100% - 2px);"><div style="padding:8px;"> <div style=" background:#F8F8F8; line-height:0; margin-top:40px; padding:50.0% 0; text-align:center; width:100%;"> <div style=" background:url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACwAAAAsCAMAAAApWqozAAAABGdBTUEAALGPC/xhBQAAAAFzUkdCAK7OHOkAAAAMUExURczMzPf399fX1+bm5mzY9AMAAADiSURBVDjLvZXbEsMgCES5/P8/t9FuRVCRmU73JWlzosgSIIZURCjo/ad+EQJJB4Hv8BFt+IDpQoCx1wjOSBFhh2XssxEIYn3ulI/6MNReE07UIWJEv8UEOWDS88LY97kqyTliJKKtuYBbruAyVh5wOHiXmpi5we58Ek028czwyuQdLKPG1Bkb4NnM+VeAnfHqn1k4+GPT6uGQcvu2h2OVuIf/gWUFyy8OWEpdyZSa3aVCqpVoVvzZZ2VTnn2wU8qzVjDDetO90GSy9mVLqtgYSy231MxrY6I2gGqjrTY0L8fxCxfCBbhWrsYYAAAAAElFTkSuQmCC); display:block; height:44px; margin:0 auto -44px; position:relative; top:-22px; width:44px;"></div></div><p style=" color:#c9c8cd; font-family:Arial,sans-serif; font-size:14px; line-height:17px; margin-bottom:0; margin-top:8px; overflow:hidden; padding:8px 0 7px; text-align:center; text-overflow:ellipsis; white-space:nowrap;"><a href="https://www.instagram.com/p/Bbrs3diAw1B/" style=" color:#c9c8cd; font-family:Arial,sans-serif; font-size:14px; font-style:normal; font-weight:normal; line-height:17px; text-decoration:none;" target="_blank">A post shared by Sam (@pikesley)</a> on <time style=" font-family:Arial,sans-serif; font-size:14px; line-height:17px;" datetime="2017-11-19T16:04:50+00:00">Nov 19, 2017 at 8:04am PST</time></p></div></blockquote> <script async defer src="//platform.instagram.com/en_US/embeds.js"></script>
+
+## Constrained version
+
+There is a [constrained variant of the problem](https://www.youtube.com/watch?v=bdMfjfT0lKk), with the restriction that a disc may only move to an adjacent stack. I've also implemented the solution for this (which maps to the rhythms of ternary) - you can run this with
+
+```
+make solve-constrained discs=n
+```
+
+(this is now the default mode for `make phat`)
+
+## Fake pHAT mode
+
+The Flask webserver attempts to detect if it's running on a Pi, and if it thinks it's not then it will log an ASCII rendition of the pHAT matrix on the console:
+
+```
+.....   .....   .....   .....   ooo..   .o...
+.....   .....   .....   .....   o.o..   .o...
+.....   .....   .....   .....   ooo..   .o...
+.....   .....   .....   .....   .....   .....
+.ooo.   .....   .....   ..ooo   ..ooo   ..ooo
+oooo.   .....   .....   ..o.o   ..o.o   ..o.o
+ooooo   .oo..   ..o..   ..ooo   ..ooo   ..ooo
+```
+
+this may or may not be useful (I'm not sure any of this is useful tbh)

lib/ruby/constrained_towers.rb

@@ -0,0 +1,62 @@
+class ConstrainedTowers < Towers
+  @@directions = {}
+
+  def initialize discs
+    super
+    @ternary = ConstrainedTowers.ternarise @count, @discs
+  end
+
+  def move
+    flip = Towers.diff ConstrainedTowers.ternarise(@count, @discs), ConstrainedTowers.ternarise(@count += 1, @discs)
+    source = Towers.find_disc flip, @stacks
+
+    @stacks[ConstrainedTowers.find_adjacent_stack flip, source, @stacks].push @stacks[source].pop
+  end
+
+  def binary
+    ternary
+  end
+
+  def ternary
+    ConstrainedTowers.ternarise @count, @discs
+  end
+
+  def solved
+    ternary.chars.all? { |trit| trit.to_i == 2 }
+  end
+
+  def inspect
+    {
+      stacks: @stacks,
+      count: ternary
+    }
+  end
+
+  def ConstrainedTowers.ternarise value, width
+    '%0*d' % [width, value.to_s(3)]
+  end
+
+  def ConstrainedTowers.find_adjacent_stack disc, source, stacks
+    begin
+      direction = @@directions[disc]
+    rescue KeyError
+      @@directions[disc] = :right
+      direction = right
+    end
+
+    case source
+    when 0
+      @@directions[disc] = :right
+      return 1
+    when 2
+      @@directions[disc] = :left
+      return 1
+    when 1
+      if @@directions[disc] == :right
+        return 2
+      else
+        return 0
+      end
+    end
+  end
+end

lib/ruby/towers.rb

@@ -1,5 +1,5 @@
 class Towers
-  attr_reader :count, :stacks, :binary
+  attr_reader :count, :stacks
 
   def initialize discs
     @discs = discs
@@ -78,16 +78,29 @@ def little_bit value, matrix, offset, side
       for i in (row..row + 2) do
         matrix[i][column] = 1
       end
+    when 2
+      for i in (row..row + 2) do
+        matrix[i][column] = 1
+      end
+      matrix[row][column - 1] = 1
+      matrix[row + 2][column + 1] = 1
     end
   end
 
+  def inspect
+    {
+      stacks: @stacks,
+      count: binary
+    }
+  end
+
   def Towers.binarise value, width
     '%0*b' % [width, value]
   end
 
   def Towers.diff first, second
     first.chars.reverse.each_with_index do |bit, index|
-      if bit < second.chars.reverse[index] 
+      if bit < second.chars.reverse[index]
         return index
       end
     end

spec/constrained_towers_spec.rb

@@ -0,0 +1,65 @@
+describe ConstrainedTowers do
+  it 'generates ternary numbers' do
+    expect(ConstrainedTowers.ternarise 19, 5).to eq '00201'
+  end
+
+  context 'diffing ternary numbers' do
+    specify 'easy case' do
+      expect(Towers.diff '001', '002').to eq 0
+    end
+
+    specify 'trickier case' do
+      expect(Towers.diff '012', '020').to eq 1
+    end
+  end
+  context 'adjacent stacks' do
+    context 'noddy cases' do
+      it 'moves from left to centre' do
+        stacks = [[], [], []]
+        expect(ConstrainedTowers.find_adjacent_stack 0, 0, stacks).to eq 1
+      end
+
+      it 'moves from right to centre' do
+        stacks = [[], [], []]
+        expect(ConstrainedTowers.find_adjacent_stack 0, 2, stacks).to eq 1
+      end
+    end
+  end
+
+  it 'follows the rules' do
+    towers = ConstrainedTowers.new 4
+
+    until towers.solved do
+      towers.move
+      towers.stacks.each do |stack|
+        expect(stack.sort.reverse).to eq stack
+      end
+    end
+  end
+
+  context 'matrices' do
+    context 'matrices' do
+      towers = ConstrainedTowers.new 3
+      towers.move
+      towers.move
+      it 'has the correct second matrix' do
+        expect(towers.matrix).to eq [
+          [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+              0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
+          [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+              0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
+          [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+              0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
+          [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+              0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
+          [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+              0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0],
+          [0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+              0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0],
+          [0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0,
+              0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0]
+        ]
+      end
+    end
+  end
+end

spec/spec_helper.rb

@@ -1,4 +1,5 @@
 require 'ruby/towers'
+require 'ruby/constrained_towers'
 require 'coveralls'
 
 Coveralls.wear!

spec/towers_spec.rb

@@ -133,12 +133,12 @@
   context 'locates the next receptive stack' do
     it 'solves the easy case' do
       stacks = [[2], [0], []]
-      expect(Towers.find_stack(1, 2, stacks)).to eq 0
+      expect(Towers.find_stack 1, 2, stacks).to eq 0
     end
 
     it 'solves a trickier case' do
       stacks = [[], [2], [1]]
-      expect(Towers.find_stack(0, 2, stacks)).to eq 0
+      expect(Towers.find_stack 0, 2, stacks).to eq 0
     end
   end
 end

towers

@@ -5,6 +5,7 @@ require 'json'
 require 'thor'
 
 require_relative 'lib/ruby/towers'
+require_relative 'lib/ruby/constrained_towers'
 
 INTERVAL = 0.3
 
@@ -21,28 +22,6 @@ def hit_phat towers
   HTTParty.patch(url, body: payload.to_json, headers: headers)
 end
 
-def fakephat towers
-  s = ''
-  7.times do |i|
-    45.times do |j|
-      bit = towers.matrix[i][j]
-      if (4 - (j % 8)) < 0
-        s += ' '
-      else
-        case bit
-        when 0
-          s += '.'
-        when 1
-          s += 'o'
-        end
-      end
-    end
-    s += "\n"
-  end
-  s += "\n\n"
-  print s
-end
-
 def display towers
   s = ''
   towers.stacks.each do |stack|
@@ -56,9 +35,13 @@ end
 
 class TowersSolver < Thor
   desc "phat", "solve the towers against the pHAT's webserver"
+  option :constrained, type: :boolean
   def phat
     while true do
       towers = Towers.new 5
+      if options[:constrained]
+        towers = ConstrainedTowers.new 5
+      end
       until towers.solved do
         hit_phat towers
         towers.move
@@ -69,28 +52,23 @@ class TowersSolver < Thor
     end
   end
 
-  desc "fakephat", "simulate the pHAT on the console console"
-  def fakephat
-    towers = Towers.new 5
-    until towers.solved do
-      fakephat towers
-      towers.move
-      sleep INTERVAL
-    end
-    fakephat towers
-  end
-
   desc "console", "solve the towers on the console"
   option :discs, default: 3, type: :numeric
+  option :constrained, type: :boolean
   def console
     moves = 0
     towers = Towers.new options[:discs]
+    if options[:constrained]
+      towers = ConstrainedTowers.new options[:discs]
+    end
+
     until towers.solved do
       display towers
       towers.move
       moves += 1
     end
     display towers
+
     puts "%s moves to solve %s discs" % [moves, options[:discs]]
   end
 end