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use std::collections::HashMap;
static DAY: u8 = 19;
fn main() {
let input = advent::read_lines(DAY);
println!("{DAY}a: {}", rating_numbers(&input));
println!("{DAY}b: {}", 0);
}
#[derive(Clone)]
enum WorkflowResult {
Accept,
Reject,
NextWorkflow(String),
}
impl WorkflowResult {
fn from(input: &str) -> WorkflowResult {
match input {
"A" => WorkflowResult::Accept,
"R" => WorkflowResult::Reject,
next => WorkflowResult::NextWorkflow(next.to_string()),
}
}
}
enum Rule {
CmpGt(char, u32, WorkflowResult),
CmpLt(char, u32, WorkflowResult),
Result(WorkflowResult),
}
impl Rule {
fn new(input: &str) -> Rule {
if input.contains('<') {
let tokens = input.split(|x| x == '<' || x == ':').collect::<Vec<_>>();
let c = tokens[0].chars().next().unwrap();
let val = tokens[1].parse().unwrap();
let result = WorkflowResult::from(tokens[2]);
Rule::CmpLt(c, val, result)
} else if input.contains('>') {
let tokens = input.split(|x| x == '>' || x == ':').collect::<Vec<_>>();
let c = tokens[0].chars().next().unwrap();
let val = tokens[1].parse().unwrap();
let result = WorkflowResult::from(tokens[2]);
Rule::CmpGt(c, val, result)
} else {
Rule::Result(WorkflowResult::from(input))
}
}
fn matches(&self, xmas: &XmasValues) -> Option<WorkflowResult> {
match self {
Rule::CmpGt(variable, value, result) => match variable {
'x' => if xmas.x > *value { Some(result.clone()) } else { None },
'm' => if xmas.m > *value { Some(result.clone()) } else { None },
'a' => if xmas.a > *value { Some(result.clone()) } else { None },
's' => if xmas.s > *value { Some(result.clone()) } else { None },
_ => panic!("invalid char"),
},
Rule::CmpLt(variable, value, result) => match variable {
'x' => if xmas.x < *value { Some(result.clone()) } else { None },
'm' => if xmas.m < *value { Some(result.clone()) } else { None },
'a' => if xmas.a < *value { Some(result.clone()) } else { None },
's' => if xmas.s < *value { Some(result.clone()) } else { None },
_ => panic!("invalid char"),
}
Rule::Result(result) => Some(result.clone()),
}
}
}
struct Workflow {
name: String,
rules: Vec<Rule>,
}
impl Workflow {
fn new(input: &str) -> Workflow {
let (name, rules_str) = input[0..input.len() - 1].split_once('{').unwrap();
let rules = rules_str.split(',')
.map(Rule::new)
.collect::<Vec<_>>();
let name = name.to_string();
Workflow { name, rules }
}
fn matches(&self, xmas: &XmasValues) -> WorkflowResult {
for rule in &self.rules {
if let Some(result) = rule.matches(xmas) {
return result.clone();
}
}
panic!("no matching rule found");
}
}
struct XmasValues {
x: u32,
m: u32,
a: u32,
s: u32,
}
impl XmasValues {
fn new(input: &str) -> XmasValues {
let mut xmas = XmasValues { x: 0, m: 0, a: 0, s: 0 };
for string in input[1 .. input.len() - 1 ].split(',') {
let (variable, value) = string.split_once('=').unwrap();
let value = value.parse::<u32>().unwrap();
match variable {
"x" => xmas.x = value,
"m" => xmas.m = value,
"a" => xmas.a = value,
"s" => xmas.s = value,
_ => panic!("invalid variable"),
}
}
xmas
}
fn rating(&self) -> u32 {
self.x + self.m + self.a + self.s
}
}
struct Workflows {
workflows: HashMap<String, Workflow>,
}
impl Workflows {
fn new(input: &[String]) -> Workflows {
let workflows = input.iter()
.map(|workflow| Workflow::new(workflow))
.map(|workflow| (workflow.name.clone(), workflow))
.collect();
Workflows { workflows }
}
fn is_accepted(&self, xmas: &XmasValues) -> bool {
let mut workflow = &self.workflows["in"];
loop {
match workflow.matches(xmas) {
WorkflowResult::Accept => return true,
WorkflowResult::Reject => return false,
WorkflowResult::NextWorkflow(next) => workflow = &self.workflows[&next],
}
}
}
}
fn rating_numbers(input: &[String]) -> u32 {
let blocks = input.split(|line| line.is_empty()).collect::<Vec<_>>();
let (workflows, values) = (Workflows::new(blocks[0]), blocks[1]);
let values = values.iter()
.map(|value| XmasValues::new(value))
.collect::<Vec<_>>();
values.iter()
.filter(|&value| workflows.is_accepted(value))
.map(|value| value.rating())
.sum()
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test() {
let input = [
"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}",
].iter().map(|&x| String::from(x)).collect::<Vec<_>>();
assert_eq!(rating_numbers(&input), 19114);
}
}
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