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www.mikescher.com/www/statics/aoc/2020/07_solution.rs

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2020-12-14 14:14:47 +01:00
use crate::common::AdventOfCodeDay;
use std::collections::VecDeque;
use std::collections::HashSet;
use regex::Regex;
#[derive(Debug)]
struct Rule {
parent: String,
children: Vec<(usize, String)>,
}
pub struct Day07 {
input: Vec<Rule>,
}
fn parse_line(line: &str) -> Rule {
lazy_static! {
static ref REX_LINE: Regex = Regex::new(r"^(?P<bag>[a-z]+ [a-z]+) bags contain (?P<inner>(?:(?:(?:[0-9]+ (?:[a-z]+ [a-z]+)) bags?(?:, |\.)?)+)|no other bags\.)$").unwrap();
static ref REX_INNER: Regex = Regex::new(r"(?P<num>[0-9]+) (?P<bag>[a-z]+ [a-z]+) bags?[.,]").unwrap();
}
if let Some(rline) = REX_LINE.captures(line) {
let parent = rline.name("bag").unwrap().as_str().to_owned();
if rline.name("inner").unwrap().as_str() == "not other bags." {
return Rule {
parent: parent,
children: vec![],
}
}
let childs = REX_INNER
.captures_iter(rline.name("inner").unwrap().as_str())
.map(|p| (p.name("num").unwrap().as_str().parse::<usize>().unwrap(), p.name("bag").unwrap().as_str().to_owned()))
.collect::<Vec<(usize, String)>>();
return Rule {
parent: parent,
children: childs,
}
} else {
panic!(format!("no regex line match: '{}'", line.to_owned()));
}
}
impl Day07 {
pub fn new() -> Self {
let input_bytes = include_bytes!("../res/07_input.txt");
let input_str = String::from_utf8_lossy(input_bytes);
let data = input_str
.lines()
.map(parse_line)
.collect::<Vec<Rule>>();
Self {
input: data
}
}
fn find_rule(&self, bag: &str) -> Option<&Rule> {
for r in &self.input {
if r.parent == bag {
return Some(r);
}
}
return None;
}
fn can_contain(&self, parent: &str, child: &str) -> bool {
let mut candidates: VecDeque<String> = VecDeque::new();
let mut visited: HashSet<String> = HashSet::new();
candidates.push_back(parent.to_owned());
visited.insert(parent.to_owned());
while !candidates.is_empty() {
let cand = candidates.pop_back().unwrap();
if let Some(rule) = self.find_rule(cand.as_str()) {
for rulechild in &rule.children {
let rcname = rulechild.1.to_owned();
if rcname == child {
return true;
} else if !visited.contains(&rcname) {
candidates.push_back(rcname.to_owned());
visited.insert(rcname);
}
}
}
}
return false;
}
fn get_full_children_count(&self, name: &str) -> usize {
self.find_rule(name).unwrap().children.iter().map(|p| p.0 + p.0 * self.get_full_children_count(&p.1)).sum()
}
}
impl AdventOfCodeDay for Day07 {
fn task_1(&self) -> String {
self.input.iter().filter(|p| self.can_contain(p.parent.as_str(), "shiny gold")).count().to_string()
}
fn task_2(&self) -> String {
self.get_full_children_count("shiny gold").to_string()
}
}