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author | June McEnroe <june@causal.agency> | 2016-12-07 22:24:05 -0500 |
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committer | June McEnroe <june@causal.agency> | 2020-11-22 00:14:24 -0500 |
commit | 05aa8ceb922c9647c1c5614b66284af28197ca98 (patch) | |
tree | 609ccc60b585d4aa37dbdc33ab35fd5ca6162d93 /src/bin/day07.rs | |
parent | Day 6 part 2 (diff) | |
download | aoc-05aa8ceb922c9647c1c5614b66284af28197ca98.tar.gz aoc-05aa8ceb922c9647c1c5614b66284af28197ca98.zip |
Day 7
Diffstat (limited to '')
-rw-r--r-- | src/bin/day07.rs | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/src/bin/day07.rs b/src/bin/day07.rs new file mode 100644 index 0000000..b2289f0 --- /dev/null +++ b/src/bin/day07.rs @@ -0,0 +1,83 @@ +use std::io::{self, Read}; +use std::str::FromStr; + +struct Sequence { + sequence: String, + hypernet: bool, +} + +impl Sequence { + fn has_abba(&self) -> bool { + self.sequence + .as_bytes() + .windows(4) + .any(|window| { + window[0] == window[3] + && window[1] == window[2] + && window[0] != window[1] + }) + } +} + +struct Ip(Vec<Sequence>); + +impl Ip { + fn supports_tls(&self) -> bool { + let any_abbas = self.0 + .iter() + .any(Sequence::has_abba); + + let any_hypernet_abbas = self.0 + .iter() + .filter(|sequence| sequence.hypernet) + .any(Sequence::has_abba); + + any_abbas && !any_hypernet_abbas + } +} + +impl FromStr for Ip { + type Err = (); + fn from_str(s: &str) -> Result<Ip, ()> { + let mut sequences = Vec::new(); + let mut hypernet = false; + + for sequence in s.split(|ch| ch == '[' || ch == ']') { + sequences.push( + Sequence { + sequence: sequence.to_owned(), + hypernet: hypernet + } + ); + hypernet = !hypernet; + } + + Ok(Ip(sequences)) + } +} + +fn solve(input: &str) -> usize { + input.lines() + .map(str::parse) + .map(Result::unwrap) + .filter(Ip::supports_tls) + .count() +} + +fn main() { + let mut input = String::new(); + io::stdin().read_to_string(&mut input).unwrap(); + + println!("Part 1: {}", solve(&input)); +} + +#[test] +fn part1() { + let input = " +abba[mnop]qrst +abcd[bddb]xyyx +aaaa[qwer]tyui +ioxxoj[asdfgh]zxcvbn +"; + assert_eq!(2, solve(input.trim())); +} |