Solution for Advent of Code 2017 Day 4

day04.rs

use std::time::Instant;

use rustc_hash::FxHashSet;

const INPUT: &str = include_str!("inputs/day04.txt");

fn parse(input: &str) -> impl Iterator<Item = Vec<&str>> {
    input.lines().map(|l| l.split_whitespace().collect())
}

fn p1(input: &str) -> usize {
    parse(input)
        .filter(|items| {
            // Passphrase is OK if all items are "newly inserted".
            let mut set = FxHashSet::default();
            items.iter().all(|i| set.insert(*i))
        })
        .count()
}

fn p2(input: &str) -> usize {
    parse(input)
        .filter(|items| {
            // Passphrase is OK if all items are "newly inserted".
            let mut set = FxHashSet::default();
            items.iter().all(|i| {
                let mut v = i.chars().collect::<Vec<_>>();
                v.sort();
                set.insert(v)
            })
        })
        .count()
}

fn main() {
    let now = Instant::now();
    let solution = p1(INPUT);
    println!("p1 {:?} {}", now.elapsed(), solution);

    let now = Instant::now();
    let solution = p2(INPUT);
    println!("p2 {:?} {}", now.elapsed(), solution);
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_p1() {
        let input = "aa bb cc dd ee\naa bb cc dd aa\naa bb cc dd aaa";
        assert_eq!(p1(input), 2);
    }

    #[test]
    fn test_p2() {
        let input = "abcde fghij\nabcde xyz ecdab";
        assert_eq!(p2(input), 1);
    }
}