「オフラインリアルタイムどう書く第20回(会議の時間)」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](https://yhpg.doorkeeper.jp/)にて過去に出題された[会議の時間](http://nabetani.sakura.ne.jp/hena/ord20meetime/)を解いてみた。
回答にかかった時間は70分程度と10分ほどオーバー。

戦略としては出題者の方の回答に近いのだが、あちらはビット演算を使っていることに対し、こちらは配列にがっつり値を突っ込んでやるという力技である。

```ruby
class Meeting
  START = 10 * 60
  LAST  = 18 * 60
  def match input
    schedule = input.split(",").each_with_object({}){|s, h|
      _, name, start, last = s.match(/^([ABIJZ])(\d{4})-(\d{4})$/).to_a
      s = start[0..1].to_i * 60 + start[2..3].to_i
      l = last[0..1].to_i * 60 + last[2..3].to_i
      h[name.to_sym] ||= []
      h[name.to_sym].push s..l
    }

    available = (schedule.key?(:Z)) ? schedule[:Z].map{|range|
      (((range.first < START) ? START : range.first)..((range.last > LAST) ? LAST : range.last + 1)).to_a
    }.flatten.sort : [START..LAST].to_a

    time = [
      freetime(available, schedule[:A], schedule[:B], schedule[:I]),
      freetime(available, schedule[:A], schedule[:B], schedule[:J])
    ].map{|free|
      free.each_cons(61).select{|f| f.last === (f.first + 60)}.first
    }.compact.min_by{|f| f[0]}

    time.nil? ? "-" : format("%02d%02d-%02d%02d", time.first / 60, time.first % 60, time.last / 60, time.last % 60)
  end

  private

  def freetime available, *schedule
    schedule.compact.inject(available){|av, sc|
      av - sc.map(&:to_a).map{|s| s[1..(s.size - 2)]}.flatten
    }
  end
end

test = <<_TEST
/*0*/ test( "A1050-1130,B1400-1415,I1000-1400,I1600-1800,J1100-1745,Z1400-1421,Z1425-1800", "1425-1525" );    
/*1*/ test( "A1000-1200,B1300-1800,Z1000-1215,Z1230-1800", "-" );    
/*2*/ test( "Z0800-2200", "1000-1100" );    
/*3*/ test( "A1000-1700,Z0800-2200", "1700-1800" );    
/*4*/ test( "A1000-1701,Z0800-2200", "-" );    
/*5*/ test( "A1000-1130,B1230-1800,Z0800-2200", "1130-1230" );    
/*6*/ test( "A1000-1129,B1230-1800,Z0800-2200", "1129-1229" );    
/*7*/ test( "A1000-1131,B1230-1800,Z0800-2200", "-" );    
/*8*/ test( "A1000-1130,B1229-1800,Z0800-2200", "-" );    
/*9*/ test( "A1000-1130,B1231-1800,Z0800-2200", "1130-1230" );    
/*10*/ test( "A1000-1130,B1230-1800,Z0800-1130,Z1131-2200", "-" );    
/*11*/ test( "A1000-1130,B1231-1800,Z0800-1130,Z1131-2200", "1131-1231" );    
/*12*/ test( "Z0800-0801", "-" );    
/*13*/ test( "Z0800-1031,Z1129-1220,Z1315-1400,Z1459-1600", "1459-1559" );    
/*14*/ test( "Z0800-2200,I1000-1600,J1030-1730", "1600-1700" );    
/*15*/ test( "Z0800-2200,I1000-1600,J1130-1730", "1000-1100" );    
/*16*/ test( "Z0800-2200,I1000-1600,J1130-1730,A0800-1025", "1025-1125" );    
/*17*/ test( "Z0800-2200,I1000-1600,J1130-1730,A0800-1645", "1645-1745" );    
/*18*/ test( "Z0800-2200,I1000-1600,J1130-1730,A0800-1645,I1735-2200", "-" );    
/*19*/ test( "Z0800-2200,I1000-1600,J1130-1730,A0800-1645,J1735-2200", "1645-1745" );    
/*20*/ test( "Z1030-2200,I1000-1600,J1130-1730", "1030-1130" );    
/*21*/ test( "Z1035-1500,I1000-1600,J1130-1730,Z1644-2200", "1644-1744" );    
/*22*/ test( "I2344-2350,A2016-2253,Z1246-1952", "1246-1346" );    
/*23*/ test( "Z2155-2157,B1822-2032,Z1404-2000,Z2042-2147,Z2149-2154", "1404-1504" );    
/*24*/ test( "Z2231-2250,Z2128-2219,B2219-2227,B2229-2230,Z0713-2121,A0825-1035,B1834-2001", "1035-1135" );    
/*25*/ test( "J0807-1247,I0911-1414,B1004-1553,Z0626-1732,Z1830-1905,A1946-1954,A0623-1921", "-" );    
/*26*/ test( "J1539-1733,J0633-1514,Z1831-1939,J1956-1959,I0817-1007,I1052-1524,Z1235-1756,Z0656-1144", "1524-1624" );    
/*27*/ test( "Z2319-2350,B0833-2028,I2044-2222,A1410-2201,Z2044-2228,Z0830-2023,Z2242-2306,I2355-2359", "-" );    
/*28*/ test( "B2001-2118,Z0712-1634,I1941-2102,B1436-1917", "1000-1100" );    
/*29*/ test( "A0755-1417,B2303-2335,Z0854-2150,Z2348-2356,Z2156-2340,I1024-1307,Z2357-2359", "1417-1517" );    
/*30*/ test( "A1958-1959,B0822-1155,I1518-1622,Z1406-1947,A1800-1822,A0904-1422,J1730-1924,Z1954-1958,A1946-1956", "1422-1522" );    
/*31*/ test( "B1610-1910,I2121-2139,A0619-1412,I2147-2153,Z0602-2111,I0841-2031,A1657-1905,A1956-2047,J0959-1032,Z2131-2147", "1412-1512" );    
/*32*/ test( "Z0623-1900,A0703-1129,I1815-1910,J1956-1957,I0844-1518,Z1902-1935,B1312-1342,J1817-1955", "1129-1229" );    
/*33*/ test( "J1246-1328,B1323-1449,I1039-1746,Z1218-2111", "1449-1549" );    
/*34*/ test( "A1958-1959,I1943-1944,I0731-1722,Z0845-1846,J1044-1513,Z1910-1923,B1216-1249", "1513-1613" );    
/*35*/ test( "A1855-2047,Z0946-1849,Z2056-2059,I1855-1910,B1946-2058,I1956-2025,Z1905-2054,J0644-1800,I0720-1618", "1618-1718" );    
/*36*/ test( "J1525-1950,Z0905-1933,A1648-1716,I2051-2054,I2015-2044,I0804-1958,B0934-1100,Z1953-2037", "1100-1200" );    
/*37*/ test( "Z1914-1956,J0823-1610,Z0641-1841,J1800-1835,A0831-1346,I1926-1941,I1030-1558,I1738-1803", "1558-1658" );    
/*38*/ test( "Z0625-1758,J1033-1351,B1816-2236,I0838-1615,J2247-2255", "1351-1451" );    
/*39*/ test( "J0603-1233,A1059-1213,I1326-2103,Z0710-1459", "1213-1313" );    
/*40*/ test( "B1302-1351,J1410-2038,A0755-1342,J0637-0658,Z2148-2159,Z1050-2131,A1543-1844,I1615-1810", "1351-1451" );    
/*41*/ test( "Z0746-2100,A2122-2156,I1022-1144,J0947-1441,A1333-1949", "1144-1244" );    
/*42*/ test( "J0718-1243,Z1443-1818,B2055-2057,A0714-1238,Z1045-1344,A1643-1717,B1832-2039,J1623-1931", "1238-1338" );    
/*43*/ test( "Z1921-1933,A1208-1418,I0827-1940,Z0757-1917,J0653-1554,B1859-1909", "1554-1654" );
_TEST

require 'minitest/autorun'

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