129 lines
3.2 KiB
Rust
129 lines
3.2 KiB
Rust
#![feature(test, iter_array_chunks)]
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extern crate test;
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use self::Result::*;
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use aoc2023::{boilerplate, common::*};
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use fnv::FnvHashMap as HashMap;
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const DAY: usize = 19;
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type I = u32;
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type Rule<'a> = (Comp, Result<'a>);
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type Parsed<'a> = (HashMap<&'a str, Vec<Rule<'a>>>, Vec<Part>);
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const LIMIT: I = 4000;
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#[derive(Clone, Copy, Debug)]
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enum Result<'a> {
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Accepted,
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Rejected,
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Jump(&'a str),
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}
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type Part = [I; 4];
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enum Comp {
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GT(usize, I),
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LT(usize, I),
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None,
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}
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fn parse_target(t: &str) -> Result<'_> {
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match t {
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"R" => Rejected,
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"A" => Accepted,
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s => Jump(s),
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}
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}
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fn parse_rule<'a>(r: &'a str) -> Rule {
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match r.split_once(':') {
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None => (Comp::None, parse_target(r)),
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Some((condition, target)) => {
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let value = parse_num(&condition[2..]);
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let idx = match condition.as_bytes()[0] {
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b'x' => 0,
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b'm' => 1,
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b'a' => 2,
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b's' => 3,
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_ => unreachable!(),
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};
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let comp = match condition.as_bytes()[1] {
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b'<' => Comp::LT(idx, value),
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b'>' => Comp::GT(idx, value),
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_ => unreachable!(),
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};
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(comp, parse_target(target))
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}
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}
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}
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fn parse_input(raw: &str) -> Parsed {
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let (rules, parts) = raw.split_once("\n\n").unwrap();
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let parts =
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parts.lines().map(|l| l[1..].trim_matches('}').split(',').array_chunks().next().unwrap().map(|s| parse_num(&s[2..]))).collect();
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let rules = rules
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.lines()
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.map(|line| line.trim_end_matches('}').split_once('{').unwrap())
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.map(|(name, rules)| (name, rules.split(',').map(parse_rule).collect()))
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.collect();
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(rules, parts)
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}
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fn resolve<'a>(part: &Part, rules: &'a [Rule]) -> &'a Result<'a> {
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for (comp, res) in rules {
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match comp {
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Comp::None => return res,
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&Comp::LT(idx, val) if part[idx] < val => return res,
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&Comp::GT(idx, val) if part[idx] > val => return res,
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_ => continue,
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}
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}
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unreachable!()
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}
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fn part1((rules, parts): &Parsed) -> I {
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parts
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.iter()
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.map(|p| {
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let mut rule = rules.get("in").unwrap();
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loop {
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match resolve(p, &rule) {
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Jump(r) => rule = rules.get(r).unwrap(),
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Accepted => return p.iter().sum(),
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Rejected => return 0,
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}
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}
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})
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.sum()
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}
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fn part2(parsed: &Parsed) -> usize {
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unimplemented!()
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}
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boilerplate! {
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TEST_INPUT == "\
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px{a<2006:qkq,m>2090:A,rfg}
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pv{a>1716:R,A}
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lnx{m>1548:A,A}
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rfg{s<537:gd,x>2440:R,A}
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qs{s>3448:A,lnx}
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qkq{x<1416:A,crn}
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crn{x>2662:A,R}
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in{s<1351:px,qqz}
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qqz{s>2770:qs,m<1801:hdj,R}
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gd{a>3333:R,R}
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hdj{m>838:A,pv}
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{x=787,m=2655,a=1222,s=2876}
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{x=1679,m=44,a=2067,s=496}
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{x=2036,m=264,a=79,s=2244}
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{x=2461,m=1339,a=466,s=291}
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{x=2127,m=1623,a=2188,s=1013}"
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for tests: {
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part1: { TEST_INPUT => 19114 },
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part2: { TEST_INPUT => 0 },
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},
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bench1 == 333263,
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bench2 == 0,
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bench_parse: |(rules, parts): &Parsed| (rules.len(), parts.len()) => (572, 200),
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}
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