2020: day07: memoize part 1

This commit is contained in:
Antoine Martin 2020-12-07 15:27:31 +01:00
parent bb5e0c9c9e
commit 213e074e6b

View file

@ -28,9 +28,11 @@ fn part1(input: &str) -> aoc::Result<usize> {
.map(|bag_rule| (bag_rule.color.clone(), bag_rule.clone())) .map(|bag_rule| (bag_rule.color.clone(), bag_rule.clone()))
.collect(); .collect();
let mut memoized = HashMap::new();
Ok(bag_rules Ok(bag_rules
.iter() .iter()
.filter(|bag| bag.can_contain("shiny gold", &bag_rules_map)) .filter(|bag| bag.can_contain("shiny gold", &bag_rules_map, &mut memoized))
.count()) .count())
} }
@ -59,17 +61,28 @@ struct BagRule {
} }
impl BagRule { impl BagRule {
fn can_contain(&self, color: &str, all_bags: &HashMap<String, BagRule>) -> bool { fn can_contain(
if self.contains.iter().any(|(_, c)| c == color) { &self,
return true; color: &str,
} all_bags: &HashMap<String, BagRule>,
memoized: &mut HashMap<String, bool>,
) -> bool {
return match memoized.get(&self.color) {
Some(value) => *value,
None => {
let value = self.contains.iter().any(|(_, c)| c == color)
|| self.contains.iter().any(|(_, c)| {
// fetch rules for this bag in map
let bag_rule = &all_bags[c];
self.contains.iter().any(|(_, c)| { bag_rule.can_contain(color, all_bags, memoized)
// fetch rules for this bag in map });
let bag_rule = &all_bags[c];
bag_rule.can_contain(color, all_bags) memoized.insert(self.color.clone(), value);
})
value
}
};
} }
fn num_inner_bags(&self, all_bags: &HashMap<String, BagRule>) -> usize { fn num_inner_bags(&self, all_bags: &HashMap<String, BagRule>) -> usize {