「オフラインリアルタイムどう書く第16回(境界線分)」の問題を解いてみた

横浜へなちょこプログラミング勉強会にて過去に出題された境界線分を解いてみた。
回答にかかった時間は50分程度。

LineSegments#countの中身は初めclineとnlineをzipし、1マスずつ比較してから結果を出していたのだが、よくよく考えれば隣り合う行のビットXORを取るだけでよいことに気付いたので書き直した。

class LineSegments
  def initialize input
    @field = input.chars.each_slice(2).map{|c| ("%06b" % c.join.to_i(8)).chars.map &:to_i}
  end

  def lines
    count(@field).zip(count(@field.transpose)).map{|r1, r2| r1 + r2}
  end

  private

  def count field
    field.each_cons(2).each_with_object(Array.new(6){0}){|(cline, nline), sum|
      ("%06b" % (cline.join.to_i(2) ^ nline.join.to_i(2))).scan(/1+/){|m| sum[m.size - 1] += 1}
    }
  end
end

test = <<_TEST
/*0*/ test( "060276724276", "6,2,1,1,0,1" );    
/*1*/ test( "770175454177", "2,3,0,3,1,0" );    
/*2*/ test( "743733377170", "9,3,1,0,0,0" );    
/*3*/ test( "724212121273", "5,2,1,1,1,1" );    
/*4*/ test( "100000000000", "3,0,0,0,0,0" );    
/*5*/ test( "000002000000", "4,0,0,0,0,0" );    
/*6*/ test( "003622223600", "0,4,0,4,0,0" );    
/*7*/ test( "520073737070", "8,3,1,1,0,0" );    
/*8*/ test( "770077007700", "0,0,0,0,0,5" );    
/*9*/ test( "555555555514", "2,0,0,0,2,2" );    
/*10*/ test( "764252427600", "4,0,4,0,2,0" );    
/*11*/ test( "774555554177", "3,3,1,3,0,0" );    
/*12*/ test( "674574754557", "11,5,0,1,0,0" );    
/*13*/ test( "000000000000", "0,0,0,0,0,0" );    
/*14*/ test( "777777777777", "0,0,0,0,0,0" );    
/*15*/ test( "774377777577", "6,0,2,0,0,0" );    
/*16*/ test( "070777777777", "0,1,1,0,0,0" );    
/*17*/ test( "373737373737", "0,0,0,0,0,1" );    
/*18*/ test( "603260327725", "30,0,0,0,0,0" );    
/*19*/ test( "466331144663", "30,0,0,0,0,0" );    
/*20*/ test( "000000000242", "3,2,0,0,0,0" );    
/*21*/ test( "567656043772", "18,2,1,0,0,0" );    
/*22*/ test( "200763012420", "15,4,1,0,0,0" );    
/*23*/ test( "400101140052", "14,3,0,0,0,0" );    
/*24*/ test( "764767476476", "13,2,0,1,0,0" );    
/*25*/ test( "001110140110", "12,2,1,0,0,0" );    
/*26*/ test( "765405076527", "16,3,0,1,0,0" );    
/*27*/ test( "377323370373", "8,4,2,0,0,0" );    
/*28*/ test( "250541131216", "11,5,2,0,0,0" );    
/*29*/ test( "744165741476", "12,3,2,0,0,0" );    
/*30*/ test( "042101000300", "10,3,0,0,0,0" );    
/*31*/ test( "002004554101", "11,3,1,0,0,0" );    
/*32*/ test( "371707762706", "15,1,1,0,0,0" );    
/*33*/ test( "130371310175", "7,3,1,2,0,0" );    
/*34*/ test( "212537003613", "13,2,1,1,1,0" );    
/*35*/ test( "157700063411", "15,3,0,0,0,1" );    
/*36*/ test( "011500036007", "6,7,1,0,0,0" );    
/*37*/ test( "743113313517", "17,2,1,0,0,0" );    
/*38*/ test( "174105270405", "13,3,1,1,0,0" );    
/*39*/ test( "427272200311", "13,3,2,0,0,0" );    
/*40*/ test( "725370332237", "12,5,1,1,0,0" );    
/*41*/ test( "005640420046", "12,1,3,0,0,0" );    
/*42*/ test( "700350001101", "14,3,1,0,0,0" );    
/*43*/ test( "577627744076", "16,1,1,1,0,0" );    
/*44*/ test( "620332232007", "10,4,2,1,0,0" );    
/*45*/ test( "260406401000", "15,1,1,0,0,0" );    
/*46*/ test( "737272723276", "5,0,0,0,3,0" );    
/*47*/ test( "000400040444", "7,0,2,0,0,0" );    
/*48*/ test( "370222002177", "13,2,2,0,0,0" );    
/*49*/ test( "372236024656", "9,3,2,0,1,0" );    
/*50*/ test( "276131137003", "11,6,2,0,0,0" );    
/*51*/ test( "742134007240", "13,4,2,0,0,0" );    
/*52*/ test( "777721775571", "13,1,2,0,0,0" );    
/*53*/ test( "700301232233", "11,2,3,0,0,0" );
_TEST

require 'minitest/autorun'

describe 'LineSegment' do
  test.split("\n").each do |line|
    t, n, input, expect = line.match(/^\/\*(\d+)\*\/\s*test\(\s*"([^"]+)",\s*"([^"]+)"\s*\);\s*$/).to_a
    ls = LineSegments.new input
    it input do
      assert_equal expect, ls.lines.join(",")
    end
  end
end