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use std::collections::HashSet;
#[derive(Debug)]
struct ScratchCard {
winning: HashSet<u32>,
numbers: HashSet<u32>,
cnt: usize,
}
impl ScratchCard {
fn get_matching(&self) -> usize {
self.winning.intersection(&self.numbers).count()
}
}
impl From<&str> for ScratchCard {
fn from(value: &str) -> Self {
let (_, sets) = value.split_once(':').expect("Should be splittable by ':'");
let (winning, numbers) = sets.split_once('|').expect("Should be splittable by '|'");
let (winning, numbers) = (
winning
.trim_start()
.trim_end()
.split(' ')
.filter(|x| x.parse::<u32>().is_ok())
.map(|x| x.parse::<u32>().unwrap())
.collect::<HashSet<_>>(),
numbers
.trim_start()
.trim_end()
.split(' ')
.filter(|x| x.parse::<u32>().is_ok())
.map(|x| x.parse::<u32>().unwrap())
.collect::<HashSet<_>>(),
);
Self {
winning,
numbers,
cnt: 1,
}
}
}
fn solve_part_one(data: &str) -> u32 {
let mut scratch_cards: Vec<ScratchCard> = vec![];
for line in data.lines() {
scratch_cards.push(ScratchCard::from(line))
}
scratch_cards
.iter()
.map(|card| card.get_matching())
.filter(|x| *x > 0)
.map(|x| 2_u32.pow(std::cmp::max(x - 1, 0) as u32))
.sum::<u32>()
}
fn solve_part_two(data: &str) -> u32 {
let mut scratch_cards: Vec<ScratchCard> = vec![];
for line in data.lines() {
scratch_cards.push(ScratchCard::from(line))
}
let n = scratch_cards.len();
for i in 0..n - 1 {
let matches = scratch_cards[i].get_matching();
let cnt = scratch_cards[i].cnt;
for _ in 0..cnt {
for j in (i + 1)..(i + matches + 1) {
scratch_cards[j].cnt += 1;
}
}
}
scratch_cards.iter().map(|card| card.cnt).sum::<usize>() as u32
}
fn main() {
let test = include_str!("../input/day4.test");
let prod = include_str!("../input/day4.prod");
println!("part_1 test: {:?}", solve_part_one(test));
println!("part_1 prod {:?}", solve_part_one(prod));
println!("part_2 test: {:?}", solve_part_two(test));
println!("part_2 prod {:?}", solve_part_two(prod));
}
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