day19

Cargo.lock

@@ -11,11 +11,21 @@ dependencies = [
  "array2d",
  "itertools",
  "prev-iter",
+ "regex",
  "rust-crypto",
  "strum",
  "strum_macros",
 ]
 
+[[package]]
+name = "aho-corasick"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b2969dcb958b36655471fc61f7e416fa76033bdd4bfed0678d8fee1e2d07a1f0"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "aoc-runner"
 version = "0.3.0"
@@ -96,6 +106,12 @@ version = "0.2.151"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "302d7ab3130588088d277783b1e2d2e10c9e9e4a16dd9050e6ec93fb3e7048f4"
 
+[[package]]
+name = "memchr"
+version = "2.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f665ee40bc4a3c5590afb1e9677db74a508659dfd71e126420da8274909a0167"
+
 [[package]]
 name = "prev-iter"
 version = "0.1.2"
@@ -167,6 +183,35 @@ dependencies = [
  "rand_core 0.3.1",
 ]
 
+[[package]]
+name = "regex"
+version = "1.10.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "380b951a9c5e80ddfd6136919eef32310721aa4aacd4889a8d39124b026ab343"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-automata",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5f804c7828047e88b2d32e2d7fe5a105da8ee3264f01902f796c8e067dc2483f"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c08c74e62047bb2de4ff487b251e4a92e24f48745648451635cec7d591162d9f"
+
 [[package]]
 name = "rust-crypto"
 version = "0.2.36"

Cargo.toml

@@ -15,3 +15,4 @@ array2d = "0.3.0"
 strum = "0.25.0"
 strum_macros = "0.25"
 prev-iter = "0.1.2"
+regex = "1.10.2"

src/day19.rs

@@ -0,0 +1,245 @@
+use std::collections::HashMap;
+use regex::{Regex, Match};
+
+enum Rule {
+    ACCEPTED,
+    REJECTED,
+    GOTO(String),
+    GT(String, usize, String),
+    LT(String, usize, String),
+}
+
+use aoc_runner_derive::{aoc, aoc_generator};
+#[aoc_generator(day19, part1)]
+fn parse(input: &str) -> (HashMap<String, Vec<Rule>>, Vec<HashMap<String, usize>>) {
+    let (workflows_input, ratings_input) = input.split_once("\n\n").unwrap();
+    let workflows = parse_workflows(workflows_input);
+
+    // screw it im using regex
+    let rer = Regex::new(r"^\{x=(\d+),m=(\d+),a=(\d+),s=(\d+)\}$").unwrap();
+    let ratings: Vec<HashMap<String, usize>> = ratings_input.lines().map(|line| {
+        let caps = rer.captures(line).unwrap();
+        let x = parse_usize(caps.get(1));
+        let m = parse_usize(caps.get(2));
+        let a = parse_usize(caps.get(3));
+        let s = parse_usize(caps.get(4));
+
+        let mut vals = HashMap::new();
+        vals.insert("x".to_string(), x);
+        vals.insert("m".to_string(), m);
+        vals.insert("a".to_string(), a);
+        vals.insert("s".to_string(), s);
+        vals
+    }).collect();
+
+    (workflows, ratings)
+}
+
+fn parse_usize(g: Option<Match>) -> usize {
+    g.map_or(0, |m| m.as_str().parse().unwrap())
+}
+
+fn parse_workflows(workflows_input: &str) -> HashMap<String, Vec<Rule>> {
+    let mut workflows: HashMap<String, Vec<Rule>> = HashMap::new();
+    let rew = Regex::new(r"^(.+)\{(.+)\}$").unwrap();
+    workflows_input.lines().for_each(|line| {
+        let caps = rew.captures(line).unwrap();
+        let key = caps.get(1).unwrap().as_str();
+        let rules_str = caps.get(2).unwrap().as_str();
+
+        let rules = rules_str.split(",").map(|expr| {
+            if expr == "A" {
+                return Rule::ACCEPTED;
+            }
+            if expr == "R" {
+                return Rule::REJECTED;
+            }
+            if !expr.contains(":") {
+                return Rule::GOTO(expr.to_string());
+            }
+
+            let (rule, to) = expr.split_once(":").unwrap();
+
+            return if rule.contains(">") {
+                let (prop, val) = rule.split_once(">").unwrap();
+                Rule::GT(prop.to_string(), val.parse().unwrap(), to.to_string())
+            } else if rule.contains("<") {
+                let (prop, val) = rule.split_once("<").unwrap();
+                Rule::LT(prop.to_string(), val.parse().unwrap(), to.to_string())
+            } else {
+                panic!("Unknown rule {}", rule)
+            };
+        }).collect();
+
+        workflows.insert(key.to_string(), rules);
+    });
+    workflows
+}
+
+#[aoc(day19, part1)]
+fn part1((workflows, ratings): &(HashMap<String, Vec<Rule>>, Vec<HashMap<String, usize>>)) -> usize {
+    let mut accepted: Vec<HashMap<String, usize>> = vec!();
+    'outer: for rating in ratings {
+        let mut wf_key = "in";
+        'middle: loop {
+            if wf_key == "A" {
+                accepted.push(rating.clone());
+                continue 'outer;
+            } else if wf_key == "R" {
+                continue 'outer;
+            }
+
+            let rules = workflows.get(wf_key).unwrap();
+            for rule in rules {
+                match rule {
+                    Rule::ACCEPTED => {
+                        accepted.push(rating.clone());
+                        continue 'outer;
+                    }
+                    Rule::REJECTED => {
+                        continue 'outer;
+                    }
+                    Rule::GOTO(new_wf_key) => {
+                        wf_key = new_wf_key;
+                        continue 'middle;
+                    }
+                    Rule::GT(prop, val, to) => {
+                        if rating.get(prop.as_str()).unwrap() > val {
+                            wf_key = to;
+                            continue 'middle;
+                        }
+                    }
+                    Rule::LT(prop, val, to) => {
+                        if rating.get(prop.as_str()).unwrap() < val {
+                            wf_key = to;
+                            continue 'middle;
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    accepted.iter().map(|rating| rating.values().sum::<usize>()).sum::<usize>()
+}
+
+
+#[aoc_generator(day19, part2)]
+fn parse_part2(input: &str) -> HashMap<String, Vec<Rule>> {
+    let (workflows_input, _) = input.split_once("\n\n").unwrap();
+    parse_workflows(workflows_input)
+}
+
+#[aoc(day19, part2)]
+fn part2(workflows: &HashMap<String, Vec<Rule>>) -> usize {
+    let mut stack: Vec<((usize, usize), (usize, usize), (usize, usize), (usize, usize), &str, usize)> =
+        vec! {((1, 4000), (1, 4000), (1, 4000), (1, 4000), "in", 0)};
+    let mut accepted: Vec<((usize, usize), (usize, usize), (usize, usize), (usize, usize))> = vec!();
+    while let Some(range) = stack.pop() {
+        let (x, m, a, s, wf_key, rule_key) = range;
+        if wf_key == "A" {
+            accepted.push((x, m, a, s));
+            continue;
+        } else if wf_key == "R" {
+            continue;
+        }
+
+        if x.0 > x.1 || m.0 > m.1 || a.0 > a.1 || s.0 > s.1 { continue }
+
+        let rules = workflows.get(wf_key).unwrap();
+        let rule = &rules[rule_key];
+        match rule {
+            Rule::ACCEPTED => {
+                accepted.push((x, m, a, s));
+                continue;
+            }
+            Rule::REJECTED => {
+                continue;
+            }
+            Rule::GOTO(new_wf_key) => {
+                stack.push((x, m, a, s, new_wf_key, 0));
+                continue;
+            }
+            Rule::GT(prop, val, to) => {
+                match prop.as_str() {
+                    "x" => {
+                        stack.push(((val + 1, x.1), m, a, s, to.as_str(), 0));
+                        stack.push(((x.0, *val), m, a, s, wf_key, rule_key + 1));
+                    }
+                    "m" => {
+                        stack.push((x, (val + 1, m.1), a, s, to.as_str(), 0));
+                        stack.push((x, (m.0, *val), a, s, wf_key, rule_key + 1));
+                    }
+                    "a" => {
+                        stack.push((x, m, (val + 1, a.1), s, to.as_str(), 0));
+                        stack.push((x, m, (a.0, *val), s, wf_key, rule_key + 1));
+                    }
+                    "s" => {
+                        stack.push((x, m, a, (val + 1, s.1), to.as_str(), 0));
+                        stack.push((x, m, a, (s.0, *val), wf_key, rule_key + 1));
+                    }
+                    _ => { panic!("unknown prop {}", prop) }
+                }
+            }
+            Rule::LT(prop, val, to) => {
+                match prop.as_str() {
+                    "x" => {
+                        stack.push(((x.0, val - 1), m, a, s, to.as_str(), 0));
+                        stack.push(((*val, x.1), m, a, s, wf_key, rule_key + 1));
+                    }
+                    "m" => {
+                        stack.push((x, (m.0, val - 1), a, s, to.as_str(), 0));
+                        stack.push((x, (*val, m.1), a, s, wf_key, rule_key + 1));
+                    }
+                    "a" => {
+                        stack.push((x, m, (a.0, val - 1), s, to.as_str(), 0));
+                        stack.push((x, m, (*val, a.1), s, wf_key, rule_key + 1));
+                    }
+                    "s" => {
+                        stack.push((x, m, a, (s.0, val - 1), to.as_str(), 0));
+                        stack.push((x, m, a, (*val, s.1), wf_key, rule_key + 1));
+                    }
+                    _ => { panic!("unknown prop {}", prop) }
+                }
+            }
+        }
+    }
+
+    accepted.iter().map(|(x, m, a, s)| {
+        (x.1 - x.0 + 1) * (m.1 - m.0 + 1) * (a.1 - a.0 + 1) * (s.1 - s.0 + 1)
+    }).sum()
+}
+
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    const EX: &str = r"px{a<2006:qkq,m>2090:A,rfg}
+pv{a>1716:R,A}
+lnx{m>1548:A,A}
+rfg{s<537:gd,x>2440:R,A}
+qs{s>3448:A,lnx}
+qkq{x<1416:A,crn}
+crn{x>2662:A,R}
+in{s<1351:px,qqz}
+qqz{s>2770:qs,m<1801:hdj,R}
+gd{a>3333:R,R}
+hdj{m>838:A,pv}
+
+{x=787,m=2655,a=1222,s=2876}
+{x=1679,m=44,a=2067,s=496}
+{x=2036,m=264,a=79,s=2244}
+{x=2461,m=1339,a=466,s=291}
+{x=2127,m=1623,a=2188,s=1013}";
+
+    #[test]
+    fn part1_example() {
+        assert_eq!(part1(&parse(EX)), 19114);
+    }
+
+    #[test]
+    fn part2_example() {
+        assert_eq!(part2(&parse_part2(EX)), 167409079868000);
+    }
+}

src/lib.rs

@@ -1,3 +1,4 @@
+mod day19;
 mod day18;
 mod day17;
 mod day16;