Day 6

AdventOfCode > 2022

Part 1: How many characters need to be processed before the first start-of-packet marker is detected?

I manually downloaded my personal day 6 input file as a logged user, and here I get the data in a more appropriate shape.

library(tidyverse)

── Attaching packages ─────────────────────────────────────── tidyverse 1.3.2 ──
✔ ggplot2 3.4.0          ✔ purrr   0.3.5     
✔ tibble  3.1.8          ✔ dplyr   1.0.10    
✔ tidyr   1.2.1          ✔ stringr 1.4.1.9000
✔ readr   2.1.3          ✔ forcats 0.5.2     
── Conflicts ────────────────────────────────────────── tidyverse_conflicts() ──
✖ dplyr::filter() masks stats::filter()
✖ dplyr::lag()    masks stats::lag()

data <- 
    read_csv(
        here::here("2022/06_input"),
        col_names = c("data"),
        show_col_types = FALSE
    ) %>% 
    pull()

head(data)

[1] "sgrrrrwcrrlqqgppfgfnngsgcgngrrllnqnndzzjgzzzjdjqdjdhhjshjhwwqnnwjnwnjwjttvgvddjrrtvtsvtvqtqhhbchcdhhnwwvqvvsbsqswqqdwdjwwjvvrddgpdpdlpljjwffqnffbllplmmwzwtzzvfzvvjbbmnmppzgzszllsqqpvqvmmzzlccjhchdhlddchdchcddnwdwhhhczzldlsdlssdmmswswzwtwzwjzwzfwwdhwdwjdjldjldlqddhttfbfnbfnfgnfnvnffsszjjsqqdzdsdrsswddggstgsgqgzqgqcqdccqcvcpcspccdgccfflppddqfdfmdffmlflplnppfvvgsgbgtgccmfccfwwthhcjcbbhbwbjbhjjtddrldlrddzjdzdttbfbmmtjmjtjzjvjvgvttthwhhgqhggcbbtqbbqgbqqvccdttfgfwfnwffbfqbfbbnlnzlzbbwnwntwtjwjnjwwsdwwcbbwhwzwhwvhhpwwnvvtvnttgtrrnjjzppmbmfmjffdddvfvjjpfpgpzzwqwpwllwjjzmjmdmdwwdrdttpmmdhdndvvpbpqbbzqzmmtdmmtddlccjvjsjrsscqqzvvbsstccvffcttwrwjjsgsttmgmvvzbbcjbjrbrddvjjnhjhphvhsszqqfrfzfssgfssgddcbbplbbsfsmfmpphssmvvcvrrcgrcgcvggrzggzjjfhjjtpphzppqtptllssbmbrrgrvvhjjnznlnggrnrsnrrphhbqhhhsthsthhhnssmsjjwjppqfqlqqgnnhnmmfsfslfllvnnsdnssgngbbjmjccsrrmjjnljlwlttpffddgbdggmbgbtbzzwgwppczcffvccnssbmmjrrfwwhcwhwqwnqqzsqqjsqqnndqdgqdqgggzjjcvvzdddhnhjnnzlnlwlzlqqvjjpprqrjrfjjrpjjnfntffqtttnjjdbjbdjbbrsrbbmrmccpllmccqrqwqnnsjjmjgjqjpqjqgjjtwwqdqmqtqqmsqmmvlldtllbcctfcccdcddcggmmmsggjddcqddbqqdgqgffststgtftbbdrbrlllnvllcflfpfdffjvvvmdmvvtfvfcvvfgghzzlgzgszzhmzzhfhllgblggfpfzfvzvdzzhsspmmjtjhjggfhggnggbtggqqtztqtmqtqddmzmrmdrmdmqqcbqcqzzvczvzfvvsggcgssjnnjqnntwtmwwhzzzhllqvlljsljjfnnjwjnwnffpggqwwvbwwdbbmbvmvlvnnnppqvqqghqgqppnllhjllvlflfpfhfjjhgjgpjpbjjdpdqdpqdpdwpwffqlffrbrjrtrvtvrtvrtrvtvltlrrvjjlttmtffhvfhfnhnlnfnvvltvlvlbbfllfnllndndcdrrnznssvpvhhhmrmlmhhrnhhpggtftddghhqrqddjttbdbqddpsdppwrwhhhgwhhqrhqrqhhqdhqddjpjqqsdsmddnqncqnqwqdwwhghbhffnsffnsszlssntnbbbfhbhwhzhdzhzbhblbzzzbqzbbgtbbcjbjtjptpwwhlwwhhmshhmbbfjbfflnnlmnnzvnnbtnbbvwvvgcggrzrffwmwhmwhwjwpwwzbbvtbtssdhdlhhdppmmcnmcmffnpfffvbfvfhvhjhffzfbzzfdfpdpzzhbzblbbmffvvcmmttdntnmtmztzbbncbctcqtcqqcvcfcwcdcchphfhjhhjbjnjtjnjwwzsstpprnnhtntvtpthpttpdpzzwcczsscqscsbbmpbbdsdlsslzszjszsczntrqjmmmfqsdwtqqflgsttwfqqvvspnlfvqlrvvbjmmpmttcdnhncmmdfhwwqdrqjqwggrbtgbrdmmrhhvqfvvhsmtfbnthrbltgvdrsbqglgjqtssbvmbjjjbbcgfftgbjmfqzggdtcfzddqlrvwqjjvnmjzjwqrwsqbjgnswpnlbdzdlcvcbqplzgqwmsntzzjhqwfjdprglcccnldfqftgttqbrmclsqtncrjbttcglcvspsgvdjqgrdzzlnhbfqbwnfqcjrrqpprjbqpzhthgsgcflqldsnwsvzgcmfrdvfmqhbcfczhschpwnmdjnjlvrwqllnnhjvjtzhcrqcwlmrqfdhvzcbnvwrgngttwlhcmmgtzwjztscjnmslbvtdrvgdprlfrhggcwtwjhblppfbpljbmwrlwqrfwjwfsftmflsdfrhlvgcbzcvhlhgclvnmtfcqttvcphgvflhdclbmtgsrldgfvtpjcphtzdctrcchwdbdbtpptdnbjnqwdrllmnbcgfltmggpqfbfpmnhcmpgsgptflglzswtmrjfzmwmwphfjngnfmmtqlrsltlvlfmwmjvvtgngllszwzdjjmbnwwgzpqltlrzfdwchgttvlhgjjhjqmlrrwsqlhsgzsgmmsgbgvrlmbprrhlgsjnsdwcbrwvqjqmfcqcwllsvggcznwpzvgpszrqwngcnchvdlrdrgtbsjdqfpsfvwdtdlqwbfjlwrmqbrhwqmfgppwvfbgthnbqnmqqhmpfwbgljcmqqbpnwvztrcrlbvtcnncwwjcbqsmbqnqtrmpwmhlvwtfmsmtpfnmphqdvqfzvmjjhnwdfjnwvmbbwvthhwzjtzzrsmqlqtnnrqjrnchqttgsptfpdcpgfmzvqhwffqmfhwqqbdhmgcrfqtwrcgtgmglmmwhvqwvglfsvwbpvhmnbqhgfgqwwnhdhvnwggsmhjfsjmsrlcvlnhrhrlhbvhdrhbplrzspdmbcnzbwlvcmztwvghlsnzmbnrpssrngpdtmgzfcbqmfdgthcscjspspmcgdmwwwfspgjwzccrfzdpbwrfpgpgzrchffmhvwwppbjwqmdzgtpfmcblzqrghzdbzqzvbnmqbdlzjrwbbhqgtdzntgdbndmndhlnhcvqtlfcrfprfrlfglwvdnszrwjdcmtstcsnvnpcldctvqpcfhjnpvscscrtfqfjcrjlrmcqjfthptbqprbvchjlqzmfcmlhmfmdhhpcqbncmcqjsdmzflwtzfdcgmrbwbcdgjmfhlshsbwmbdcbfbvmqcgwlqpprjfrhzvsjmcjdfnwhcffhtnqpznfzpttsqqwcsvpdhdfbggzpngvbvdlpmvfjjlcfmbvmfqsczprtlnwvqnnlcrdnvpmcbrzvlfgscbcwtrbcpdnpshhmrqmhnwcndptljhwpvtcflqgmzjsfmfdzwwwhnbpzjwzgqmdcdbtfhwtgvcscbdqlcmppwjgghvrmqpwfbnjfhfcrccfzjvtjsjcsmhncdjlclvhfsvlcjcnpbqqqdjmjdbggmfwswvdjscvgrdbpcrcqtndswgdnznzpwtcdgvcrrqpdcpbmbdjrsgnfvgwpgpzttfmsczcmjvhmdpbpmjjcjsvbvbwjpwtwpsdddlsnvrshqvmwsjwwvqnczzljjfptcszgpndgczprbvjbnqpwgzmnlhvbsfbtjnwbtlzqgnmzbmqgqvwzltvqczfpdzfzsfhqlmtfcbfdqtnwzbvqblqmzvmnspntqtqdglrdmdntrghwvpfrbjgpzvrnppvnvfgwdzlvhtcscclbtftlvsprwhjvjlhrhfdgzbfbfphzbhtfdlpzcshhfzhtdvggnnbqvnrwvnhvgjgjpcrztqjmtzlzlrlmndfvctzjdpnmlgmsppqdrzmptvrsptvmmbvbwvhwptrtlfdqdqwfgldtbhqdhszcmwqnhswrdhgmgvbvbhwhlpcflsrwlvsvhvctmwwhtlgmshdqflwsdjbbzgbvbwpfncgqjzfjvmzzhgdzjvghtrtsmwgzpdrngwdbtfzrqsgdmwtdhsftfqcnmjtrqqwthcbgtmqnjvjzzplrzllnjqddvbwnglhtzljwjvscdfdnsvmrgwhjrhlrqpqgmzstnwwjpddhdbsnnsqvtsdhtmfdmbcpzwqmbhhjhcfzbvvglhfdltrmbstjhsqrbs"

I build a helper function and check some examples:

• bvwbjplbgvbhsrlpgdmjqwftvncz: first marker after character 5

• nppdvjthqldpwncqszvftbrmjlhg: first marker after character 6

• nznrnfrfntjfmvfwmzdfjlvtqnbhcprsg: first marker after character 10

• zcfzfwzzqfrljwzlrfnpqdbhtmscgvjw: first marker after character 11

library(slider)

start_distinct_marker <- function(data, n) {
    data %>% 
        str_split_1("") %>%
        slide(~.x, .before = n - 1) %>% 
        map(function(x){
            n_distinct(x) == n
        }) %>% 
        which.max()
}

"bvwbjplbgvbhsrlpgdmjqwftvncz" %>%
    start_distinct_marker(4)

[1] 5

"nppdvjthqldpwncqszvftbrmjlhg" %>%
    start_distinct_marker(4)

[1] 6

"nznrnfrfntjfmvfwmzdfjlvtqnbhcprsg" %>%
    start_distinct_marker(4)

[1] 10

"zcfzfwzzqfrljwzlrfnpqdbhtmscgvjw" %>%
    start_distinct_marker(4)

[1] 11

Here the result:

data %>% start_distinct_marker(4)

[1] 1855

Part 2: How many characters need to be processed before the first start-of-message marker is detected?

Here the full code for both parts:

library(tidyverse)
library(slider)

data <- 
    read_csv(
        here::here("2022/06_input"),
        col_names = c("data"),
        show_col_types = FALSE
    ) %>% 
    pull() 

start_distinct_marker <- function(data, n) {
    data %>% 
        str_split_1("") %>% 
        slide(~.x, .before = n - 1) %>% 
        map(function(x){
            n_distinct(x) == n
        }) %>% 
        which.max()
}

data %>% start_distinct_marker(4)

[1] 1855

data %>% start_distinct_marker(14)

[1] 3256