Day 6 solution.

2022/input/day06.txt

@@ -0,0 +1 @@
+rnttlvtttmnmpmhpmmzvmmhpmmnrntnnsnrnndvnddmbbtptssjcczmmbwmbmwwmmflfggwzzhjjgppwrwdwqwbbbmwbwgggqccmlmdmgdgqgpqgpgzzndddgdbbsvvfsfppwjwzjjcnjccwrwrprgppbpddnccjggfrggqngqgdqgddvsshqhmqqfvqvlvwvnwwmccrpcczvcczzgsgwwlggqsggmdgglblpblltbbzrbzzcscgccwssbddsmddzzvvhjjwjwrjwrwfftmttplldnllqttdhddmvdmmhsmsmqsqwqpqbpqppqdppbnpnhhppjbbrzrbrggdbddnrdrzrdrpdppzzfzrzgzllwlwzlllwtltslttlmtmqqbbzmzhmmjjwrjrrnzrzhzmmtbbrppmmfddjhdjdsdllrbbpfphpzpwwjvwwdpwpzwwzrrfnfwwfbbpttzjtjptpvvsfvvljjrzzmdmsddpvpgvvdcdwcwhwghwggrjjhdjhddzhhwbhwbwwbrwwrfrmfrfvrfftzzqrzqrqtrqtrqtrqttgctclcwlwwvqqnlnqlnnndmnmggznzhzqzggzrzbbrwbrwrvvscvvmvhmvvbsbjsjfjpfpqpbbbbjtjptpprnndpnnrsswffmnnjhhpqhqwhhbwhbhgbbfrbrjjpmjmzzdzjdjffcvvtwttrrcscvcncqcfcwwpgpfptpcpspllcfcssgbglgdllcdcmcpcqclctcvtvvbhbbdhhczhzshzhbhchzchchlcllwswqqmpmbbqwwzgzhggczgzffsgggjjlcjjpnjjfqjfjvfvrfrlrvvpfpcfcbffnmfmbmbgggplldblddvcvjcvvmbmmmrvrvvnhhqttgdgvdgdqgddcsclljplpbbsvbsbfsffshsgslsllzztggttfccctwtswwrvwvnnfbnnvjnvvlgvvfppmvpmmvpmmcttjffgsffcllncntcncfclcgcppvdvpvrvbrrnnvrvhrvrzvrvnrvrdrnrqrnngsshqhcqqbfqqzmmmzjzqztznttjffqzfqfbqqsggclgclcddtqqdppbjppqvpqvvmqmqnqcnqcqcqvqjqzqbzzbrrgfgddgtgnnpjjbzjjbbtstzszwswggfffmnnpllfvvnwnpwpqwqwlllqlmmzcmcrcmrcmrcrffnrnssjjrdjjwwqgwqgqdggwzwjzzbfbpptctchthbbbqsqggrllldwdffvwwlrwwljwjnncmmjmvjmmqnnmrrgjgvvpqqbppqlpqllqnqdndwwlppcjcdjjcnnmddffgjjrwjrwjjhvhqvhhfssrtsrsgrrwjwhhbqqpzzrdrhrqhrqrprqqmllsszhzllcdllpmpbbmsmjjmwmssvlslwwmtwmmgvgcvggzcgzgddsjsjfsssftfcchhfmfcmcpcpvcppqggjddljjbttwrrhghqggpghgngzngznnzqnnssqlqmqbmmmqdqqhttnqqjhhphrhccbggmjjpwpbwpprdrvvjzvvtctzzmpphwpwdpdvvhbvvdvsdsjdjbdjdljjstswttnhhbfffmnngddlglqggvzvlzvzqqvbqbvbjbnjjsvjjwpjjzshrdtrjttvqnbltrfpvnztrwzrtgjpzgqdjfglqgjrgdzbhqpghdbfhlfjhbfjfjppfgljmgwljlsbmltgztthnzvdrgqlgddvqhzctdgcphfqvnpjjgzwqfvnhvzdrwtpgfdjpqnfshslqmplcprdntnhqqbqptwzvdddhcjcqrfhjqnjvpnhttblwgjwlfwntdchgfjmdbgtqtdgnzbqwzzcltwtmtqtdbvjtfvlzpcvgmrfqwfhwqmhvwhftzgmhshffnjwqbvztszsrrglqvhfpqmbnqjsfnwdwgdtmztbvqrmztfctmvptbwnfzfgdztjgnqsrsqqqnrpgzsqszzwwwgqnnnrdzhzdbqjgbvncprzcjqchzfgnclbrmphbsdwwpvwjwlbshhgjfbhjjtdqrmrcjfnrrhqrpsbglthzpvfglqspttdpwlljhnlrjpzchbrqcgtmcscjnwvpztfjdcwbnbgmbpgdthgnhbrtwftnscbsrndghbslflpcpjwbcjnhzcwdcslmzqbtrlnzmntlpjcsctnsqwtbffqlhfgcsflvfwnmczvsbflnnnzpfjfrcwhhcbtbjcbghtcwcgdbrwrgfgvpwtcwlwcmnmrtcrjbwtwlrfstztsghfvrfjzzpswpqfqpvqstvbhqfjlgmtdlhqrhwzqpnqpllnlgzwptbgftmblqcwfcllbwfzdhrndfrvdvwzqvhnghlzvhldnnvrgqvlpfdnpmcgddjmstzsqfvzwftflrwtzqwjbbqhjpfbdztdfsgsztvvrvslgspgpdcmwszdfsddqhpzpsjgqmgzqvhchlgrmcmzwzbtwfphvgcdmhfdczhffgmqpncdjszzgwfvwsqddvbcgngbjwhmphjsmjthvbthhfwdtqmjctcmdpqpsdrnrzdgzgzctbhwsgvtjgwjbsnnjmpmqgwrnqfqbpnrpddjsrsvmcshhthwfrwmqsrjhlsrgfzvwmdzhwrvchppqldghgzflrnwqnvntmtdwmrpgbdbzvcmnqstzntvllcgzsnvrhqzsfncznhgrggmvrmgsqmhbdsjbsqqhzppfcwdrgdvfjdscrvpwtsdmcnczwbbjhvddprwtzfwslcfdcrqfszcgmhtdfvlqzqtvwngzvmmqcrqpzwzhggjnphsrmnctnfhtppglspnvzrsqfgzdfrrwbzbqwvbvbnzgmdrqrnsvdpvlgcmnggsbmbtfwrvdjrtgtgcqscnfpgswgsngdqnnscffdcnlrcpdpcbpzvqcrtjhlwvgnfhhqmprthrtcvcjjwgprqqdwfbgmzlwttjpvcjzfwbdhvngsjpgtqsvbldbcvhjhzbjzblqtqhlnbzzqfcpnzdhbplztcgvzhbgshqbccgwzhftqvtwzbwmnfrsgphhhgtsmwlqhlcchtbtggqwmbdthhmqqjtfdvfpddfdrtfjbpmwtcbfnrhwcnpdqrdtsfdmjfzdwwgnftnwpssgqtlpdbwhnzcnfmppclsswbhcdghpnslwjznqszgdtrnpncsqsnbrplrfwpbnfnvttlzcjtvhzcpzmhfsfzfjlzqqnprpdvwbfthmrswqrcqqwrnwzmgjqqsnqdblssmhngjjvprmqbswtgzzvprwhrgjqshvmwzgrgfmzlgrtzbmdlzncwqdftfsndvdfmmplswdbjtbcbvcvtpjvrqpghczpqvvpqwfbfhllbpvrrfsmsjhqbldcrwvzvcvzfffqvplbfbdbwctbjsljlfwtbcnpsbtpmcqgdvltmztvrcfsprbnvwplwhncgsdnrdmqnmcvpvvrlmlwtgvrnwvzsfctdlcfvtgqmpnbwcbwvfpmqnbjvwffpjtvvgflhrnlngrzhhttdtdbvscftsqtvbrgzfgsjvwhzjcbsqcttlgwmhhvjhwhgmmdtflfdbvnhgcblqmwjfsqnngjqfbvdnsfbgwjfhpgdgvhpbvlrtpcpvhrbtqpbffzcqrvbqwvqmmrcwtnvcgwvsqzvrwdbcnjshbnbftmmvrmjvgfdwbsjvqfdwnnvqqhbmshcrclrwhfhbtnwqvmrrvdwgcwcsrhdbqndsthmrmbjhttjtzmlflbrmhlcgsbdjcjcvwcjffnqrntpflrgfcngpchtrzpnflwjvcgbwtsnjfqsggwmwhdvbzdpjmtwlmrslnjsndjtgjmmwmdgtnfrztppzqvqhbfzqpsdhvsshddlzwcmsndrpqhndsrjnngnmgmzrvchwlqgdnbssbhpbpgwpsrcnbphpslvqplhpgdhmrnwwjmhvnsfjmrfwtvjjrmgptvjffhbgpmfgmgrcjrwqhccssrqjpljbpwcvsfdtmbhzsmsjsgblgpcqszsttfclrjcnsslmngmbmwqfhddbvmbvwmrmvglsl

2022/src/day06.rs

@@ -0,0 +1,30 @@
+use std::io;
+use std::fs;
+use std::collections::HashSet;
+
+use crate::utils;
+
+pub fn execute() -> Result<(), io::Error> {
+    let data = fs::read_to_string("input/day06.txt")?;
+
+    let packet_marker = find_uniq_index(&data, 4);
+    let message_marker = find_uniq_index(&data, 14);
+
+    utils::print_step(1, &packet_marker);
+    utils::print_step(2, &message_marker);
+
+    Ok(())
+}
+
+// Returns the (1-indexed) position where the first sequence of unique characters of `length`
+// ends in `data`
+fn find_uniq_index(data: &str, length: usize) -> usize {
+    for (i, substr) in data.as_bytes().windows(length).enumerate() {
+        let mut uniq = HashSet::new();
+        if substr.iter().all(|x| uniq.insert(x)) {
+            return i+length;
+        }
+    }
+
+    panic!("No unique string of length '{length}' found.")
+}

2022/src/main.rs

@@ -2,14 +2,14 @@ use std::env;
 use std::io;
 mod utils;
 
-const LATEST: u8 = 5;
+const LATEST: u8 = 6;
 
 mod day01;
 mod day02;
 mod day03;
 mod day04;
 mod day05;
-// mod day06;
+mod day06;
 // mod day07;
 // mod day08;
 // mod day09;
@@ -38,7 +38,7 @@ fn main() -> io::Result<()> {
         3 => day03::execute(),
         4 => day04::execute(),
         5 => day05::execute(),
-        // 6 => day06::execute(),
+        6 => day06::execute(),
         // 7 => day07::execute(),
         // 8 => day08::execute(),
         // 9 => day09::execute(),

2022/src/utils.rs

@@ -3,6 +3,7 @@ use std::io::prelude::*;
 use std::fs::File;
 use std::fmt::Display;
 
+// Returns the contents of a file as an iterator over strings.
 pub fn read_lines(filename: &str) -> io::Result<impl Iterator<Item = io::Result<String>>> {
     let file = File::open(filename)?;
     Ok(io::BufReader::new(file).lines())