day06.rb

require 'rspec/autorun'
require 'set'

def marker(input, length)
  input
    .chars
    .each_cons(length)
    .map(&:to_set)
    .find_index { |set| set.size == length } + length
end

RSpec.describe 'Day 6' do
  it 'works for the example cases' do
    expect(marker('bvwbjplbgvbhsrlpgdmjqwftvncz', 4)).to eq(5)
    expect(marker('nznrnfrfntjfmvfwmzdfjlvtqnbhcprsg', 4)).to eq(10)
    expect(marker('mjqjpqmgbljsphdztnvjfqwrcgsmlb', 14)).to eq(19)
  end
end

p marker('wzsspbssbhshchmmrmprmrfrsfrrjhjphjjtppbfflqfqppdhdbhdhbbjgghgzgsgfsfhfhvvwcwhwwnppsbsggqnnvvtffpssjfjnnltntdtdddptprppjmmqssrlrplllfrrzggbmmlmnmtnnzddfdgfdfsstbstbbzcbbcjcvvfwwwzlzssglsgllnbnmbnmbbgmmppmwwsrrzqqvgqgnqnmmswwrnnbsnnbdbwwqnwqnwwzzqwzqzjqqwbqbccjcwwjlwjwppqfqjffwddrzrjzrjzzzhchjjlqqrggzvvnlvnvjvhvnvjvbbvdvldldbbwddtsscbbhccmbmbppbmmgjggcjjlrrwjwtjwwmffgddwvdvbdbvvhchmhmdmwwbjbjcbbcmbmmslmlslsjjrnrjrjpjcjgcjcjbbwsbsbfssjzsjsggcmcsswgssbbqpbqqdsdqqztzmzpmpbmbvbjjtrjtthwhbhnbhnbnssvpvsppgrrcwrrmqqhpphrpphchvhphqhbqbtttllsrlsrshrrmhmvvrmrnngbgnbnpbprrrftfjtjwwmrmvmcmvmrmwmssrccfbbhppjbpbwbqwbqbzzfmzmtttjbbvcvppmwwrbbzsbzbfzfdzzhrhzhvvsqvsqsnslljwllqlwllvccnttzhtzzpspqspqsqgsssvnsvshvsvqvnvlldbbfdfmmpbpgphhpqhpppchhbfbrfrllntnznrrhdrdhhdhjjgwwqhhfssjbjwjqqbffvvcrchccwmcwcllljtjrrqgrrdcrddvfvwvzzjqqcffgjgzzdhdwdssffjjhccggmtmltlhtthzhvhlvlddsfsbbtjbjcbjcjzcjjpfjfzzpnnbtbqtbqtqptpnplllbzbllhbllnqnttpddqvdqvqmmjnjggnnnhqqfcqcffqppdgpddvqddmhmrhrtrmrzmzhzpzlzqlqpqhphrpppjqqppzbzmmjgggqtggtjthhlclnclcnccmcppdcpddqrrfgrgbbhwhdhrrqtqpqjpqjpqjqqmcqmccnngqqqmtqtssnvnzvvpcpwcwwqcqqqfcqffsvsmvmttttmrrzssghgssjmsmbmvvwggggzhhfvdpgjmmvzbfjghqhrfbpmbvjzwvfmcthrqwdhghpwsspmhpqnmwhjzpnlzfnvhdnnrqwnvctbmjqzhqrpjlwrssdlwqzmsfrfzmgjhnwwnwczswnhsdbvqbmdlvntsdrhrjjcjjhpbblgwhjwdcdjtpvtmslwvncwdjbwzvbpzbvddvssnrhtshrcvnhqnpmjzfswqbbrztnwjcpflfbhnphfwmjvnvtswgfttgjcqcngmmwjlfsprwfcfwcmgrgbnqmzbtzbtbztngvrzpsnrzvhbsdjnzpwwzllgnfdrlwpmnrznqsqcmvnfbnhqjddvcjmtgbpbmsgqdqzflmlmqncmhwltrmdmgnwpfwddrdpfhsgsnggchzjhgpwrsmdzgjtrgmnprhbwbcbpzbdvvstfqcnqzbdjqpmrdbtgcthtclftghhmnrzrjqqsbndhpvmdpfpwdlhvmczvdfgvpqclssvlhqnhlcfnfbvtspdzmgzdctvpdcwchtqhpsgmmblspjdlvgblbpgrfrgnqqsphcsrgfsdmpqscbjmnqrfbcwfthdtswbzthpnvsfbntnbmmgpfzlqwhppvvdrmwbqzbgppbgsqmjfqtmntgwpnccthftwdmvwmnchlbjhsnmbhndczbrhhjpbvnjdzrcndbbmfwfwsjwfgbqhwhrsvlngsbhhlrdjzzbmjpsqhlpzwcsntjhlmngblspmsjrjwsjsrqwnrcwsmcsbmpjwrthbqhrschrmrppnnbmjbvjzlmzsrfdwqlfnfjljftjvzsqdwlhbblqcdlqjbprpcllhlhmwrbrlgfrcqshrtjpnmhljttdvpfnhdjqvjhhfczwvbzqgnzgljcfrbpgwnfhfchwzqmqqzpbcdpqmnbrppzblnnzqrfnmgtljwnfgzwvnjppdbdhbznvpgwhbdjjvlspgwgjsmfsvllpgwlfnnptmwnfsshjjvqzjwrqpvmsphpmftqdllqqdzcjwfvpftgvspprdwvvcnglmbpntghntdwpjvvsppgjvnbjgvtzchtqtwbddncsbrfcvrnvlggvwgmmnfzrswnzjrwthzmdsmzqmzsnrqsnslnhmfqljnnnzshqfqshrhhjmnhdgphctswdbhnrcgnzmmzqpjqbtdfhhltsmvvtntbgsznshhsghblhlhqpmdcfhmnfzvhgnfsfflcfwbfqzmccrjdpfvphtqbrdnzjfmfhbzqcpdnjdcgwprvchlzrcvrghgjqncjvnndbcshntrfsbsnmjlhclnzpfdgztflcpwqpnvlscfndwqzfvcmpgfncszpmwcsrdbrrhdjvmthslfvmlgpqhlgwhqnjljcvhswbsbqfrfhvzwjvdmhzsgbmbmfnbpclqdwhvrlpppszptjvwtvdmfltfqqgjttdggcvllblnnhjqnjzhvpgpzzpzwbpjqbthnjjlmsjgjzqwnjlqrcdmmvsldtcrzqdrcmwqhnhfghdlmzwcspgmlpzhbdsmlwlqnhhvcvdfzmvfwpbfmjtdllprfqzzjpbrshdzgspsrlrwrhdpmznzzqngwrzqpmtwgbsswrnnnfctjhbcftnslsqwjvmfwfdvfqcnsvfsvgstgbzpmljjtlvtnfsdzpvcgbjqwgbgzqbjfgltqvnhffflsbjzfqfrfbssrvvwqvqptmhrbgllqjwptrzgvqgccsrvbgtvmzfzlmtqrgfwhzddsptclbhjlwqfntvjqdvcddnffmbtqrnsvtmlvljcqdsrpggcmqvmmlzwwbgznhblwzjdppvtqzjvcmtfzhdzjplrdbrfrgzpldvnsgqlbwbmfvrbgwzmjmmqdfgwtbgtzmdqnvqbwvcfjhddqvnjtjlhhjnltbtqqvblwlmglrqcrcfjvdntrnqzzbmrjqglmrdcjgnshcghtprjqqsdrmgdnzmzcfqqdtjtrqgtqtgrpmmgzjtcrznmqccjbdpbvrnnbmbzvgdcnrczbctbrsrrqrjnfcdpzlnngwvcdtbbgssvhpptntqdzhcqtlpvzjbfgzggrgrcgtdfjbwdcrpztnfcdbscnlmqmwcbmtnddgbmhwsgvcfdcmhlsvtnqtmrnsjzhppgwvzlmhwwmpfjzrfbhsgntzrdhwswrnfmmmczqrvdrqnhgrvqbdddhglwsftsljvgbnjqfwfzsspdqvgsnlgfsfpvdrjhzcldtrmjjrmdhvvfrjldhhtqnvsvlldjpjbpwstfsmrpmbqbnnpvqtbgjvblthbmwqtfcfgnjscvtbvlqcmlhffpzgjzfscsqwnhrjhvbrrzwqvbjwtwhtqsdbssfgncppnsfgfltdcbjqjzqqtprsbvjzhmchnltvmbsvpvhgzhfhbrnttsqbcmwpdnwqqgdrjrdwdhtzwsmcdffqgsddvbzfjhtfhtnfdbfrwmdtcqshfjrcpswzcptgwgmctpmzjdbqlmqwthmnfplmctpsslcsdtqpqhjtmjdnmnqnjgchwstsmtpvsmgpsbfgwqnzhrdgdvcdlcldfcmjvsdldgbmhltjhczffwmzqssnhfnwftfgpshntjbpjdffjpcmcpwhclrrwqcqzmntjglzgcfrplfpvprtpvpjdlcrfwrtrzdzmhsrsmdcpqqrqgvfpdbmzbzqdfhpplmgfrdghclbclgswvwhhdvcpmpzflpffmptcrwglftztccrpbrvmpnqmqdgjgrrlbtqtvgcjpljttwtdslqjqlsdpblgrqbrtbmtblfbqtbvsqhpqzpqfhjqpmjrmcvqmsbbpjpdncgnjftclbltwszrrfzqbjcdtphcvpmbhppvwjwlprgmghrjzzgnvzlvghnjbzqjpdgzfsnjchpbzqdzpsjmsrvvqwjcpwznlpbjldlrdfqtrzhqzcnpjqbbbf', 14)

https://youtu.be/W1d-yFjnI1I