Day 6

Section

defmodule Day6 do
  def run(message_length, input) do
    input
    |> String.graphemes()
    |> Enum.reduce_while({0, <<>>}, fn
      c, {i, acc} when byte_size(acc) < message_length ->
        {:cont, {i + 1, acc <> c}}

      c, {i, <<_::binary-1, tail::binary>> = acc} ->
        if has_repeats?(acc) do
          {:cont, {i + 1, tail <> c}}
        else
          {:halt, {i, acc}}
        end
    end)
  end

  for i <- 0..2, j <- (i + 1)..3//1 do
    def has_repeats?(bin)
        when byte_size(bin) == 4 and
               binary_part(bin, unquote(i), 1) == binary_part(bin, unquote(j), 1),
        do: true
  end

  for i <- 0..12, j <- (i + 1)..13//1 do
    def has_repeats?(bin)
        when byte_size(bin) == 14 and
               binary_part(bin, unquote(i), 1) == binary_part(bin, unquote(j), 1),
        do: true
  end

  def has_repeats?(_), do: false
end

Day6.run(4, "bvwbjplbgvbhsrlpgdmjqwftvncz") |> dbg()
Day6.run(4, "nppdvjthqldpwncqszvftbrmjlhg") |> dbg()
Day6.run(4, "nznrnfrfntjfmvfwmzdfjlvtqnbhcprsg") |> dbg()
Day6.run(4, "zcfzfwzzqfrljwzlrfnpqdbhtmscgvjw") |> dbg()

input =
  "sgrrrrwcrrlqqgppfgfnngsgcgngrrllnqnndzzjgzzzjdjqdjdhhjshjhwwqnnwjnwnjwjttvgvddjrrtvtsvtvqtqhhbchcdhhnwwvqvvsbsqswqqdwdjwwjvvrddgpdpdlpljjwffqnffbllplmmwzwtzzvfzvvjbbmnmppzgzszllsqqpvqvmmzzlccjhchdhlddchdchcddnwdwhhhczzldlsdlssdmmswswzwtwzwjzwzfwwdhwdwjdjldjldlqddhttfbfnbfnfgnfnvnffsszjjsqqdzdsdrsswddggstgsgqgzqgqcqdccqcvcpcspccdgccfflppddqfdfmdffmlflplnppfvvgsgbgtgccmfccfwwthhcjcbbhbwbjbhjjtddrldlrddzjdzdttbfbmmtjmjtjzjvjvgvttthwhhgqhggcbbtqbbqgbqqvccdttfgfwfnwffbfqbfbbnlnzlzbbwnwntwtjwjnjwwsdwwcbbwhwzwhwvhhpwwnvvtvnttgtrrnjjzppmbmfmjffdddvfvjjpfpgpzzwqwpwllwjjzmjmdmdwwdrdttpmmdhdndvvpbpqbbzqzmmtdmmtddlccjvjsjrsscqqzvvbsstccvffcttwrwjjsgsttmgmvvzbbcjbjrbrddvjjnhjhphvhsszqqfrfzfssgfssgddcbbplbbsfsmfmpphssmvvcvrrcgrcgcvggrzggzjjfhjjtpphzppqtptllssbmbrrgrvvhjjnznlnggrnrsnrrphhbqhhhsthsthhhnssmsjjwjppqfqlqqgnnhnmmfsfslfllvnnsdnssgngbbjmjccsrrmjjnljlwlttpffddgbdggmbgbtbzzwgwppczcffvccnssbmmjrrfwwhcwhwqwnqqzsqqjsqqnndqdgqdqgggzjjcvvzdddhnhjnnzlnlwlzlqqvjjpprqrjrfjjrpjjnfntffqtttnjjdbjbdjbbrsrbbmrmccpllmccqrqwqnnsjjmjgjqjpqjqgjjtwwqdqmqtqqmsqmmvlldtllbcctfcccdcddcggmmmsggjddcqddbqqdgqgffststgtftbbdrbrlllnvllcflfpfdffjvvvmdmvvtfvfcvvfgghzzlgzgszzhmzzhfhllgblggfpfzfvzvdzzhsspmmjtjhjggfhggnggbtggqqtztqtmqtqddmzmrmdrmdmqqcbqcqzzvczvzfvvsggcgssjnnjqnntwtmwwhzzzhllqvlljsljjfnnjwjnwnffpggqwwvbwwdbbmbvmvlvnnnppqvqqghqgqppnllhjllvlflfpfhfjjhgjgpjpbjjdpdqdpqdpdwpwffqlffrbrjrtrvtvrtvrtrvtvltlrrvjjlttmtffhvfhfnhnlnfnvvltvlvlbbfllfnllndndcdrrnznssvpvhhhmrmlmhhrnhhpggtftddghhqrqddjttbdbqddpsdppwrwhhhgwhhqrhqrqhhqdhqddjpjqqsdsmddnqncqnqwqdwwhghbhffnsffnsszlssntnbbbfhbhwhzhdzhzbhblbzzzbqzbbgtbbcjbjtjptpwwhlwwhhmshhmbbfjbfflnnlmnnzvnnbtnbbvwvvgcggrzrffwmwhmwhwjwpwwzbbvtbtssdhdlhhdppmmcnmcmffnpfffvbfvfhvhjhffzfbzzfdfpdpzzhbzblbbmffvvcmmttdntnmtmztzbbncbctcqtcqqcvcfcwcdcchphfhjhhjbjnjtjnjwwzsstpprnnhtntvtpthpttpdpzzwcczsscqscsbbmpbbdsdlsslzszjszsczntrqjmmmfqsdwtqqflgsttwfqqvvspnlfvqlrvvbjmmpmttcdnhncmmdfhwwqdrqjqwggrbtgbrdmmrhhvqfvvhsmtfbnthrbltgvdrsbqglgjqtssbvmbjjjbbcgfftgbjmfqzggdtcfzddqlrvwqjjvnmjzjwqrwsqbjgnswpnlbdzdlcvcbqplzgqwmsntzzjhqwfjdprglcccnldfqftgttqbrmclsqtncrjbttcglcvspsgvdjqgrdzzlnhbfqbwnfqcjrrqpprjbqpzhthgsgcflqldsnwsvzgcmfrdvfmqhbcfczhschpwnmdjnjlvrwqllnnhjvjtzhcrqcwlmrqfdhvzcbnvwrgngttwlhcmmgtzwjztscjnmslbvtdrvgdprlfrhggcwtwjhblppfbpljbmwrlwqrfwjwfsftmflsdfrhlvgcbzcvhlhgclvnmtfcqttvcphgvflhdclbmtgsrldgfvtpjcphtzdctrcchwdbdbtpptdnbjnqwdrllmnbcgfltmggpqfbfpmnhcmpgsgptflglzswtmrjfzmwmwphfjngnfmmtqlrsltlvlfmwmjvvtgngllszwzdjjmbnwwgzpqltlrzfdwchgttvlhgjjhjqmlrrwsqlhsgzsgmmsgbgvrlmbprrhlgsjnsdwcbrwvqjqmfcqcwllsvggcznwpzvgpszrqwngcnchvdlrdrgtbsjdqfpsfvwdtdlqwbfjlwrmqbrhwqmfgppwvfbgthnbqnmqqhmpfwbgljcmqqbpnwvztrcrlbvtcnncwwjcbqsmbqnqtrmpwmhlvwtfmsmtpfnmphqdvqfzvmjjhnwdfjnwvmbbwvthhwzjtzzrsmqlqtnnrqjrnchqttgsptfpdcpgfmzvqhwffqmfhwqqbdhmgcrfqtwrcgtgmglmmwhvqwvglfsvwbpvhmnbqhgfgqwwnhdhvnwggsmhjfsjmsrlcvlnhrhrlhbvhdrhbplrzspdmbcnzbwlvcmztwvghlsnzmbnrpssrngpdtmgzfcbqmfdgthcscjspspmcgdmwwwfspgjwzccrfzdpbwrfpgpgzrchffmhvwwppbjwqmdzgtpfmcblzqrghzdbzqzvbnmqbdlzjrwbbhqgtdzntgdbndmndhlnhcvqtlfcrfprfrlfglwvdnszrwjdcmtstcsnvnpcldctvqpcfhjnpvscscrtfqfjcrjlrmcqjfthptbqprbvchjlqzmfcmlhmfmdhhpcqbncmcqjsdmzflwtzfdcgmrbwbcdgjmfhlshsbwmbdcbfbvmqcgwlqpprjfrhzvsjmcjdfnwhcffhtnqpznfzpttsqqwcsvpdhdfbggzpngvbvdlpmvfjjlcfmbvmfqsczprtlnwvqnnlcrdnvpmcbrzvlfgscbcwtrbcpdnpshhmrqmhnwcndptljhwpvtcflqgmzjsfmfdzwwwhnbpzjwzgqmdcdbtfhwtgvcscbdqlcmppwjgghvrmqpwfbnjfhfcrccfzjvtjsjcsmhncdjlclvhfsvlcjcnpbqqqdjmjdbggmfwswvdjscvgrdbpcrcqtndswgdnznzpwtcdgvcrrqpdcpbmbdjrsgnfvgwpgpzttfmsczcmjvhmdpbpmjjcjsvbvbwjpwtwpsdddlsnvrshqvmwsjwwvqnczzljjfptcszgpndgczprbvjbnqpwgzmnlhvbsfbtjnwbtlzqgnmzbmqgqvwzltvqczfpdzfzsfhqlmtfcbfdqtnwzbvqblqmzvmnspntqtqdglrdmdntrghwvpfrbjgpzvrnppvnvfgwdzlvhtcscclbtftlvsprwhjvjlhrhfdgzbfbfphzbhtfdlpzcshhfzhtdvggnnbqvnrwvnhvgjgjpcrztqjmtzlzlrlmndfvctzjdpnmlgmsppqdrzmptvrsptvmmbvbwvhwptrtlfdqdqwfgldtbhqdhszcmwqnhswrdhgmgvbvbhwhlpcflsrwlvsvhvctmwwhtlgmshdqflwsdjbbzgbvbwpfncgqjzfjvmzzhgdzjvghtrtsmwgzpdrngwdbtfzrqsgdmwtdhsftfqcnmjtrqqwthcbgtmqnjvjzzplrzllnjqddvbwnglhtzljwjvscdfdnsvmrgwhjrhlrqpqgmzstnwwjpddhdbsnnsqvtsdhtmfdmbcpzwqmbhhjhcfzbvvglhfdltrmbstjhsqrbs"

Day6.run(4, input)

Day6.run(14, "mjqjpqmgbljsphdztnvjfqwrcgsmlb") |> dbg()
Day6.run(14, "bvwbjplbgvbhsrlpgdmjqwftvncz") |> dbg()
Day6.run(14, "nppdvjthqldpwncqszvftbrmjlhg") |> dbg()
Day6.run(14, "nznrnfrfntjfmvfwmzdfjlvtqnbhcprsg") |> dbg()
Day6.run(14, "zcfzfwzzqfrljwzlrfnpqdbhtmscgvjw") |> dbg()

Day6.run(14, input)