From 05aa8ceb922c9647c1c5614b66284af28197ca98 Mon Sep 17 00:00:00 2001 From: June McEnroe Date: Wed, 7 Dec 2016 22:24:05 -0500 Subject: Day 7 --- src/bin/day07.rs | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 83 insertions(+) create mode 100644 src/bin/day07.rs (limited to 'src/bin') 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); + +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 { + 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())); +} -- cgit 1.4.1