129 lines
3.2 KiB
Rust
129 lines
3.2 KiB
Rust
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#![feature(test)]
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extern crate test;
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use std::collections::HashSet;
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use aoc2021::common::*;
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use itertools::Itertools;
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const DAY: usize = 4;
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const BOARD_SIZE: usize = 5;
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type Parsed = BingoGame;
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type Board = Vec<HashSet<u8>>;
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#[derive(Debug, Clone)]
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struct BingoGame {
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input_numbers: Vec<u8>,
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boards: Vec<Board>,
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}
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impl BingoGame {
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fn mark_number(&mut self, n: &u8) {
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for board in self.boards.iter_mut() {
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for winning_set in board.iter_mut() {
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winning_set.remove(n);
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}
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}
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}
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fn find_winner(&self) -> Option<&Board> {
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self.boards.iter().find(|b| has_won(b))
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}
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}
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fn has_won(board: &Board) -> bool {
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board.iter().any(|s| s.is_empty())
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}
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fn parse_input(raw: &str) -> Parsed {
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let (input_numbers, boards) = raw.split_once("\n\n").unwrap();
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let input_numbers = input_numbers.split(',').map(|n| n.parse().unwrap()).collect();
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let boards = boards
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.split("\n\n")
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.map(|b| b.split_ascii_whitespace().map(|n| n.parse().unwrap()).collect())
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.map(|v: Vec<u8>| {
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debug_assert_eq!(v.len(), 25);
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let mut rows: Vec<HashSet<u8>> = v.chunks_exact(BOARD_SIZE).map(|s| s.into_iter().copied().collect()).collect();
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rows.extend(
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(0..BOARD_SIZE)
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.flat_map(|i| (0..BOARD_SIZE).map(move |j| i + BOARD_SIZE * j))
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.map(|i| v[i])
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.chunks(5)
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.into_iter()
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.map(|c| c.collect()),
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);
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rows
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})
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.collect();
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BingoGame { input_numbers, boards }
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}
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fn board_score(board: &Board, current_number: u8) -> usize {
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let remainder: usize = board.into_iter().flatten().unique().map(|&n| n as usize).sum();
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remainder * (current_number as usize)
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}
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fn part1(parsed: &Parsed) -> usize {
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let mut game = parsed.to_owned();
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for n in &game.input_numbers.clone() {
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game.mark_number(n);
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if let Some(board) = game.find_winner() {
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return board_score(board, *n);
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}
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}
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unreachable!("Game should have ended at some point")
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}
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fn part2(parsed: &Parsed) -> usize {
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let mut game = parsed.to_owned();
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for n in &game.input_numbers.clone() {
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game.mark_number(n);
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if game.boards.len() > 1 {
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game.boards.retain(|b| !has_won(b));
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} else {
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if let Some(board) = game.find_winner() {
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return board_score(board, *n);
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}
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}
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}
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unreachable!("Game should have ended at some point")
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}
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fn main() {
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let input = parse_input(&read_file(DAY));
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println!("{input:?}");
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println!("Part 1: {}", part1(&input));
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println!("Part 2: {}", part2(&input));
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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use aoc2021::*;
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const TEST_INPUT: &str = "7,4,9,5,11,17,23,2,0,14,21,24,10,16,13,6,15,25,12,22,18,20,8,19,3,26,1
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22 13 17 11 0
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8 2 23 4 24
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21 9 14 16 7
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6 10 3 18 5
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1 12 20 15 19
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3 15 0 2 22
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9 18 13 17 5
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19 8 7 25 23
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20 11 10 24 4
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14 21 16 12 6
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14 21 17 24 4
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10 16 15 9 19
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18 8 23 26 20
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22 11 13 6 5
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2 0 12 3 7";
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test!(part1() == 4512);
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test!(part2() == 1924);
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bench!(part1() == 0);
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bench!(part2() == 0);
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// bench_input!(Vec::len => 0);
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}
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