Advent of Code - Day 6: Tuning Trouble

Part 1

Input

input <- readLines("input.txt")

head(input, 10)

[1] "qhbhzbzzfrzrbzzcjzjrrvcvrvqvvnggnngcgssswbblplrlflfnnnmmjppgddqndnrnlnccpfcfjcjvjdjqqqmhhmwhwmmsnsvsjvjnvjnvjvsjsmjsjccwcqwcqwqjqwjwmwbmmbzbsbvsslbsbbbntnvvphpqqvrrtbrtrfftppbggpzzfhfcfsfmssffmbmzzmqzzblzzzmwwnggjwgjwgjgpgmmjvvmcvmmcfchfhllwmlljqqldqdqttsgsvscsmsnsmstmtssvgsgddwdffbppwfpplhlchhhdvvdrrmttmptmmmjsmshmmmgqmgggzjgzzmwzwcwhchqqfpfvvbqvbqbrblrrmtmstmmjvmmdnmmzczdzpztppjhjjwzjjjtdjjpljpjcppjllsffhbffbhhgttqjqzzfzbzcbzcbcrrjjrwrgwwbcbpcccctrtqtfqqfjjpgpdgdfgfrggpjjljglgclcqcqmcqmmgjjllpmphpjjgfjjqrrbppwmpmccftctjtjgjtgggzffcggwzzzdjdzzlgzgjzzvqvppczzjnjvvfhhtwtttdwtdtvddpzpnpcnppmvmcmcsmstthctchcggtssdttvztvvldlfftqqbzzjttvzztppscctzccgmcmvmhhchcscbbshbssgwwthwhmwwcgwcwrrvrzvrzzzvhvdvmmprrdmrmfmrmbmjbbmqbmbqqhbbszsjjlqjljtjstshhgphpffdhhtggtgbbqcqgqccfffcpcbpbfppwqpqcclbbwdwsscpchhfpfmpfmflfnnmggwrrznnghgvhhghrrhwrrcschcscqcmcfcvvgzztjtqjjshspsqsmmjnnmttsshvhmmqfqzztbzttvhttmwttnqnfncfcpfflmllmtlmmphmhlmmltmtztcczhzbbfmmlglnnfpppqplljwjfwfdwdzwddszddqzqnzzzwwlzzqvvjlllrwlrrmpmrmbmpplpspqsqmqcmcjjshsvstvvwtvthvvrfvvqmmjpmjmrjmmlvvnnrjjrcrwrhwwqzzvgvngncgcqqcffmfzfssbnbfblbggwhggmtgtvvqhhpttbcbczcjjbqbhqbhqbbccbhbqhbbmppdlpdllbvvdpvdvwvsvppllgblbttmcmtccbsswmswwwzfwfhhtfhthctchcfhhhfjjvhjhgjjjcwjwggrtgrttcqcwcswccfdffvpvtptprrvjjqvjjghggshhwmmcscmsmhmvmppprfrwwrhhvghhtnhncctbbbwzzbgzgdzgdzdpdvpvbbwgbwwrqwrqwqbqvvclccfcfzfdfrrthrrqcqddplpqlppbbfrfmmrmnnwhhgddmwwrzrsswpwhwdwhhsmhshqsqllbvlbllwbwbpwwfwmwsmspsvsdsbscctpctppvvpggtjjdmdqqgqbgglccvzcvcnczcgzgmzznpzzpcpnpvpcvvffrttqrqttflfbfjfnnwnlwlhwwqzqnqfftstdsttglldwwgqwwvqqzczfzdffbfsfssfwswdwnwdnnbcncwctttvsvjsvsrvvbtvvzhhvjvtvtjtsjjvhjjwpjjnzzpczzppgcpgcpgcgsgvsgvsscrcpcpspllzvzddpssssdpsddhffllzmzhzfhhdvhhvbvwwpwqpwqpwwmvwmvwvgvmvpvmpmrmzrrblltjtggvnggvppthhzjhzhffrvrhvrhrlrslsflfhhtvhvmmhppjgpjpcccmqcqvqhvvfssrtmnwjjslwhjgpvrwspjlwdwrmvfgwmplrmjrllndrjzvjfbwvzpjpfqrnjspwcpsgcvdlmfdfrvwdcvmbrnzncgnqlcvgqtpsbbpvprncdsgvpqbpcnffwqmmfsvnzspchhrlnzbhcdfdgtsllmqfbrcqwbmmzrfvsghjpmrndsdbqvtprmblnbvbnpvhtphbpjwdssvwgdzwztbpzdcsqzldjzrgcwhhspblrtncvntppcgttlflflnntcnzpbpgsclcjvbjhldcdzwjjhnfwzjmgcwtljhvbncwqnjhbrhfqcmnsdvntsbgnpqttzvbhzzpdznrhjpnsqzsztsblstbghlpwbmqjctlnqnttwshfvmjdhgbgjdhbzrfjqndrrhlqcmplczjtwpstlsmwwzqzmgvhsvjgbrtfwmvwlbhpccbqvmfmlgmbmbmldbcwmmhpnnbnffbnqgwhclgpzgbpjqvzmqhhhpltnwrdfrrnmlfrzflpnjztlnfzzzgmncprtblpsvrqgrnzbzfzhzhjjjdrnpvjpnwmlmlgvvtqmdvpnhvcrdmthcnnnvhnzmvgrtdvcthgjtvcgmtpsvmfztrflrrzbmcfhftwwcnjfpjtsnzjccmvdnrrwvbfjgcjttdvzncqhlqqphwphclztbhlqcfmnhcjmsscplnrsjqpdzrrzbthbcdnrzgdmstpgqqsvzclvmzjjdfqhhhttwcjtmwcbltghmslqvltqbjqqjpjvgntvnlttjcnhltflglgsmjwjjfldpfgjgrhttbwfhpsdbsmsfmfbtjlnhvjfqjrqhwdrcwpfthdgqzjjjfcvgdffrhvvwzfghpszmjjgscjvjnlgnbfbgfrbbzbzbnzngthrddfmsgsqqdddpfqwlchfblrvjdcgnzfzwmmnmvnzmpfmhbbhsbfdfclzcnbrlgpbsvfgfpshrpvpgccmmghphrcvzwnlqjcfwrtwvlvcsdldldvnpwgrcsqlftllcctnvcwbdswvqlzwzzbpmvvctcrgnjfstbqvnzczrjlljfqzrwtfwmlvvdfbfntrrljtbrtbdfsqpnppfbppbsmghbnqddhrvwmgzttnqjrqlfrdhqjndmnjlbctgclltmznmrqtfjsjwnztdvhnhlfwpnnqlhhsrfzglsnrdnfvrqssbtlthzfnjdvrcgzsbnpdgqhhrlwspfqfqpvzdfwgrlhwplzvbzprsqzcwvhggvzpgjztnvwvddsflgsvqljmmhhdzqsqmthwzvllqwmsnvdpdbjcgdtrsnmwhnzhbhgjssstmhrpssnhnntmrbbbjgmjqtncbdljcgtmbctpgdrnqcnrpssrdtpbsmlzlcztbrggglswnjzqgbsmgbqdzppqrwgtnlrjrvlpnqlcdwhltzzlqdwwrglldzcqrjtjtlgdqrtwzjgtdthsdccsmsrbjjsgdqcwdltvnjwtddsnpnsvzcdbfqnvsjbngqrztmbrnbvhhjzdtqrgldpvjqjpnshbjdsdgbjdjzdmrvzhwmtgcjrfnprstqgfgnwfpcjzhlnwpdbtqbspssqdrzhmmsrqtlwngvbrvgdgztnrlwcnqwvcdmhhdrmpfqbgbjpvzwbsbgcpsnpjplcrjdhflqvsdctclqqnmprngtvbmlmpqrsqdsrzgsmzmsczpsnmfmtfnjvnddjhqbjdvtgftjfvjhgpjqdhlszqjmcbnwrppzwjvmgblspjmfhjdbnmrllnfqlpcbndvqdzhhmmrpsljgdshpnrgnmwfjsdncqcwlctccrqghfdbsqqbnwctcqpvlrqqqvdjwlcnzmvdmcvlwnftjnqqldfwhmdtcpnlgfcdjdrfvmwqdzsjzctmmmrswhlwthttvcsqqscdcsmjgqfjhswlpsfjrppdmbwrthcwszqwwgnjsdqdrswmnzbrvqcwlrlwwvjmrrhsnzprggbzhhdqwvnspsmzzqdtbphzvwrzvqnbntjndrwllzwchczdwvnfjjdwfhdlgncftldzwdtjzjrmnfwwgmqdrltmgrfsjztfcvwjsggtvbnsvthflwfdtljrgqhmfqhmhfffqhtgwtlmwgzsglqnfwnrnvgvbdgqjrqtsmgsmzdpffnnzwlpbqphqmgdzspfrdqlptwmfwlgnqqdhtbbjtfhllrhhdcszjtmrprzhzzlgjqbcnhzcmhzrsnmmrzztffrldthhfvwhgjhwmjfbdvnllfmlpdsldjnpcwlpbwqzdwbgjb"

Code

get_marker_index <- function(characters, marker_length) {
  for (i in seq_along(characters[1:(length(characters)-marker_length)])) {
    set <- unique(characters[i:(i+marker_length-1)])
    if (length(set) == marker_length) {
      return(i+marker_length-1) 
      break
    }
  }
}

characters <- unlist(strsplit(input, ""))

result <- get_marker_index(characters, marker_length = 4)

Result

The number of characters that were processed before first start-of-message marker is 1802.

Part 2

Code

characters <- unlist(strsplit(input, ""))

result <- get_marker_index(characters, marker_length = 14)

Result

The number of characters that were processed before first start-of-message marker is 3551.