62 lines
1.4 KiB
Rust
62 lines
1.4 KiB
Rust
use aoc::*;
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const INPUT: &str = include_str!("../../input/02");
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fn main() {
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println!("Part 1: {}", part1(INPUT));
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println!("Part 2: {}", part2(INPUT));
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}
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#[test]
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fn example() {
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assert_example!(part1, "02-test", 1227775554);
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assert_example!(part2, "02-test", 4174379265);
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}
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fn part1(input: &str) -> usize {
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parse_input(input)
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.map(|r| r.invalid_id_sum(is_doubled))
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.sum()
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}
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fn part2(input: &str) -> usize {
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parse_input(input)
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.map(|r| r.invalid_id_sum(is_repeated))
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.sum()
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}
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fn is_doubled(id: usize) -> bool {
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let id = id.to_string();
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let (hi, lo) = id.split_at(id.len() / 2);
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hi == lo
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}
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fn is_repeated(id: usize) -> bool {
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let id = id.to_string();
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(1..id.len())
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.map(|prefix_len| &id[0..prefix_len])
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.any(|prefix| id.trim_start_matches(prefix).is_empty())
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}
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struct Range {
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from: usize,
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to: usize,
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}
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impl Range {
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fn parse(s: &str) -> Self {
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let (from, to) = s.split_once('-').unwrap();
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let from = from.trim().parse().unwrap();
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let to = to.trim().parse().unwrap();
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Self { from, to }
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}
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fn invalid_id_sum(self, is_invalid: fn(usize) -> bool) -> usize {
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(self.from..=self.to).filter(|&n| is_invalid(n)).sum()
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}
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}
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fn parse_input(input: &str) -> impl Iterator<Item = Range> + use<'_> {
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input.split(',').map(Range::parse)
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}
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