From e887a8ad0d307e6af568a820316023e243fa1341 Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Tue, 6 Dec 2022 08:27:47 +0100
Subject: [PATCH] Implement 2022 day 6

---
 2022/benches/days.rs |  2 +-
 2022/inputs/06.txt   |  1 +
 2022/src/day06.rs    | 69 +++++++++++++++++++++++++++++++++++++++++---
 3 files changed, 67 insertions(+), 5 deletions(-)
 create mode 100644 2022/inputs/06.txt

diff --git a/2022/benches/days.rs b/2022/benches/days.rs
index 77e9853..d5385c1 100644
--- a/2022/benches/days.rs
+++ b/2022/benches/days.rs
@@ -8,7 +8,7 @@ use criterion::BenchmarkId;
 use criterion::Criterion;
 
 /// Number of days we have an implementation to benchmark
-const DAYS_IMPLEMENTED: u8 = 5;
+const DAYS_IMPLEMENTED: u8 = 6;
 
 fn read_input(day: u8) -> Vec<u8> {
     let input_path = format!("inputs/{:02}.txt", day);
diff --git a/2022/inputs/06.txt b/2022/inputs/06.txt
new file mode 100644
index 0000000..bd24b2b
--- /dev/null
+++ b/2022/inputs/06.txt
@@ -0,0 +1 @@
+grvrnvrnnjljbjqjpqjjvhhzwwrbwwbblrltrrpbbbbqnnqbbbbsvbvmbvmbbrsrqrzrllwbbbqzqrqnqrnrjnnjccdggwqqhrrjcjmjmllgrlglhlclmlvlvsshwwsggmfmdfddgdfftrrczrcczhzppgdgrdggghmmdwwqgggslglfgfcgccmjcjwjrwjrjcrjjsgjjvddpwpgpbbgwbgwwhnhfftbffhpfphhfqfrqfrfnfpprvrsrhrfrllfhhrsrhssvfsvsnvsnsswtwtlthllrjjwddtggzczgcchwcwppfbbdvdrdzrdrvrwwsbsfbssqfsfjsjcscttlztllgjjlbbdsdtssvvvwlvlqqnhqqtdqtddjcdcjjpbphhgtgtqtzqqzhqqtgtvtmvtvrvqrvvfmfmppzzbwwnddzttfpfrrlddbppfqppnwnswwdhwdwjjqljqqthtnhnddgmgcmgcmgcmmfmfttrzzfdzztllmjlllgcgbbcqcvccpnndbdjbjmmzbztzptzpprpddptpprhhvlvmlmpmmljjnnjsjfjjvgjjvzzfgfzfbftbftttgstgstgtpggflfcfqqtctltgltldlzdlzzmmlddnvddzfddppmnpptzptpvttwstwswvwrvvbfbjjjbmjjdvdvrvdddrwrhrzrqqhghhrwhwhrrmppsgpsgszzdfdfwwmtwtvwvgvffmqqqtqntqnnjcncbnbwnnzggrdrqqjbqjjwjqqqwlqwlwzlljhhfsfsqsrqqhwqqwbbqbvvlflrrlglbbjhhjmhjjcmcjcgczcfcgcqqczcnnvjnnlddmpmcppgvgjgddvrrnsnmnqmqgmmnppwgwcgwgssbddgtdgdgmdgmgvvmjmvmjmvvsfssdgdghdggbfbqbdbjbsbmmrpmrprggbllwrwpwtppzvppzsssdnsdnnvnhvvvzvfzfqqnnmlnltldtdvdbdblddsmmlccmlmvlmvmmcsctctrtsrstsbsrshsddlmddmppgsscttnrtrqqcvcwwlnlznnnvcnvvtnvnbnmbmvmppjgjdjtddmpdmdvvmgvvdqdlqlhhzccsggjdjsdsttctjctjtfjttppdzpzzbjbwwmwbblslzslzszlzrrcbrrfggvcczjjtbbdnnggbwblwlbwlwqqfvfqfddrrfccvlllhmhhhrthrthrrnbnzbbpzplphprrrnbbghhnshnhbblqqqvwwffnmnmhhtccpqpvqvbvnvvfnfsnffdjdllwffcddgcgrgjrggchcpcddtbbdtdmtdmmhhtphtpppclcpcvcjvcjjfqfzqqphpnhnrnhhpdhhtfhhbbmqmfmsmvssgqqfssqgglnnqmnmbnmbbllrdrgdrdvrdvdsvvnddgtgddcdqdsqdqbqqlhhwdhdgdcgcdchchrchhpvvpgvgrrfggwfwgmpddbhfngtrwswfszgsggnpsntjpslrpjqsffzrlnbnzdtqpqtjzwlhhgrsrbvnccnsjmzcbqgcbtbqlzhnpnhhrrvqwjwzzvrlcrmjhcscrqhpqmfzbnvcwwqhcjjlnggmpbwztzfswmsbjshnsgfmdlzvzczhrdwgwbghszpnbfpctrshbfhspsczcqcrrqcpwwpfzhjqtpqgjbztrpzrlgfdjbmlwdvlvnfmdzbwsbbhlbszvwcpztlchjrqbmsftltmqpfgdpmdgjvwqqtjsqlfqrwmsnlqgsbqfwsdnfvzthmbplvszfcmlptlcjpnfpjsphsmmjplwjqphgvzbtbjtpttqhlwtgnrjvmvsfsztmsqszzlhqqhfslsvhzgtsssfctzgsqbgdzlpwbsmpcnjqshhhcwqdsdzdhnjfqzqnqdlrpddcgrgldgqbjmdtwgppdczzrjvmcfqjbpjzbtjmgdphlbwnsnpfdqlhwvvmpwzsrztnwvtlbphljmjwsgbphgmwhdmfhpvsmvsjccjhfvqtvfmmlnggncltvtrgmbtfqsvfnlvcmjnjwzcrpjnsgntvhjbtdlptshbhhchqmsprhqzdnfpjqccdfvnzjtlbsmmwvzlwlvmsbrnhqctvtvbfhntdctjnrbcrrlmsnwbbjbcbbgrrhfqwzwwfgvsvgbwnttghtgpspzwzfhffsqjvwwttntnvlwftsfvtttgnprzrzsghvjrdtsfdvzswhmrfcdqsgvrlhzbnvbmjlqrftnnbtwqtvlvwznfbslhdqjbntdgpprfqchjvgvzjssdztjlzwfljjmfvzrbbtczggzqwrnqqgzzcbqjcpfqfrbwtdjrrvbszsjdjcpdfjscsvnltcgwvqsgnhbfgnfnddnpmbzbptrmvqzpvbdpfdvtlmgnnjwflgdbfnmvsdnmlvgcpwflwvdbtbfwtfpsmqsplnzwlwgvbjrhghwrnrswsggbqpdjcjrgbgnsqdvwzzwftvjqgjzzcdvpbbjzpphmbcqmrjvgqwfgrsnqvhwflmhgrlvbpwdcsrlqwfrwppqbrdhwqtvczpclpsbsjcptgblbbsqmbhjjgzwvlcnhnzcttmpjsgchmppgphqlzlcsqcgbbjgtjjvmttdztfdptzgvmpnqrcmpmcdlpnbztllvqbggqbqhlqvdwsrwzsjwfrqvcbvsgfdptmrzpvdfblmhlzrvpmsljlqqzrhlnmwncpfhvqlsbtrjbfcrnfvjvddrhdbbczjdsrdvzlbqrccssdzcpmdsqbprjppfzdwfdswptgzcmjqfhcwsqfqhvrslffqfbcvhdzljzrmtwmfdwzdhhjcmbjtvjhzzwfqhrcslztdbnlwmmhbbbgdscjcdzftnchqfnflnsdqjscfrqpnfbftpzvtmrwncqfqqflschpfnjsjlqcjdjgtwpqhgcnjdmnnvmmpwdspmnrgqrptqwcvbtdwpqlbtwpqgwgfrzlrhtvrvzhmhmwhfdsrhpcczqfltsgtgrfwcvlcvtlhqqwnrqgzpnzbfmzbdwqwbsfvbshrgzqdbgvrhzhzlbqsfzttmsnmrqmwgtzbvdqdrbgcpclzjrhdbjtpcdbbznjgtbwbqrnpvffdmwtrbhhstcmnjcwbbnmpbvmjprtzgcptmtrffwhvfgdljnrbbrblbfbgdwtjrtgqgrpvpgjqrjzczvvlspgdbzftqgqvgdqlglbgvgjdcztznszcwfqhmwbrbjcfstzdcmdsssqfhtzpdgmzjscvbdzgbhhgdqgvfwrzmhdrhlsvlzjjzbzdljcbhncppwrtptjgszlqsrqpzqcsgvdvzmgvwgsncnbffttslphcstqvfwbwzbflmshcbnhpljgqwmmwwzlgpbcqnrtqlwcjcrclfdrnnmvtbfdztdfvtqrsgdptfcfpzpsldhzmrngggfvdqggtlfqqwsldprcffsstnnpmsbbvghdbpprqbssnprdbqclzqtgsrczwcvqwrrfmmfwsndvtvqljwwglrgbphdvvwgctbbmtrbpzqtspgrlhmnhjcdwhwvssgspzjbcfjttjqbdpdmptfzzjcfqljpqddfssmffqprvbptfvdshsdmfmdtmlbnmbmjjjsgmlmwmgcwhbrbgchrstptvdlqgddfzddlzhwjmsvvcjwvqtzjtsctfmzchlbrvlgdzbvdlbfpvhptpltrdmcgjghcpwvwqqnrzdtnmgdncplhdpsgpnbprbgshffwwsdhpgqsbmwdtpnhhltlcqfrjtswcchzvlhdgrmjwhgwppdjqlgmdhwbllqvzrchgclmqdlghjsvmwlflmhhmdzbfjhjnvwphnjbclmdpgflqgtfsmsjslntfcmtbphnrgpdcqtjzjttdtgjmvhzsrfnrjqssvwpcslpfstbpfsrsntmftmdgsqrrsnddqfmchrhtlhmqndvvllnvltdzfphjqnvmcdsgfpcmjftgdpntjzplqljhtthvnbzbzwvfnqsjvnfwhmtbsspjslgfjvdgfjpwrsgqwntntjcqtdgnhnsfwhhqfwbwhdrftj
diff --git a/2022/src/day06.rs b/2022/src/day06.rs
index 745aff3..f36ac0d 100644
--- a/2022/src/day06.rs
+++ b/2022/src/day06.rs
@@ -1,9 +1,70 @@
 use anyhow::Result;
 
-pub fn part1(_input: &[u8]) -> Result<String> {
-    todo!()
+fn find_first(input: &[u8], unique: usize) -> Result<usize> {
+    #[inline]
+    const fn index(c: u8) -> usize {
+        (c - b'a') as usize
+    }
+    let mut seen = [false; 26];
+
+    let mut first = 0;
+
+    // Loop invariant: input[first..last] contains only unique characters
+    for (last, &c) in input.iter().enumerate() {
+        if seen[index(c)] {
+            while input[first] != c {
+                seen[index(input[first])] = false;
+                first += 1;
+            }
+            first += 1;
+        } else {
+            // New unique character found: input[first..=last] contains unique characters
+            if last - first + 1 == unique {
+                return Ok(first + unique);
+            }
+
+            seen[index(c)] = true;
+        }
+    }
+
+    anyhow::bail!("Did not find unique sequence of length {unique}");
 }
 
-pub fn part2(_input: &[u8]) -> Result<String> {
-    todo!()
+pub fn part1(input: &[u8]) -> Result<String> {
+    Ok(find_first(input, 4)?.to_string())
+}
+
+pub fn part2(input: &[u8]) -> Result<String> {
+    Ok(find_first(input, 14)?.to_string())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    const SAMPLES: &[&[u8]] = &[
+        b"mjqjpqmgbljsphdztnvjfqwrcgsmlb",
+        b"bvwbjplbgvbhsrlpgdmjqwftvncz",
+        b"nppdvjthqldpwncqszvftbrmjlhg",
+        b"nznrnfrfntjfmvfwmzdfjlvtqnbhcprsg",
+        b"zcfzfwzzqfrljwzlrfnpqdbhtmscgvjw",
+    ];
+
+    #[test]
+    fn sample_part1() {
+        const CORRECT: &[usize] = &[7, 5, 6, 10, 11];
+
+        for (&sample, &correct) in SAMPLES.iter().zip(CORRECT) {
+            assert_eq!(find_first(sample, 4).unwrap(), correct);
+        }
+    }
+
+    #[test]
+    fn sample_part2() {
+        const CORRECT: &[usize] = &[19, 23, 23, 29, 26];
+
+        for (&sample, &correct) in SAMPLES.iter().zip(CORRECT) {
+            assert_eq!(find_first(sample, 14).unwrap(), correct);
+        }
+    }
 }