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use {
anyhow::{
anyhow,
Context,
Result,
},
std::{
env::args,
fmt,
fmt::Display,
fs::File,
io::{
BufRead,
BufReader,
},
path::Path,
},
};
#[derive(Clone)]
struct BingoBoard {
size: usize,
values: Vec<u8>,
called: Vec<bool>,
completed: Option<u8>,
}
impl BingoBoard {
fn new<'a, I: IntoIterator<Item = &'a u8> + Copy>(grid: I) -> Self {
let size = 5;
let values = (&grid).into_iter().copied().collect();
let called = vec![false; grid.into_iter().count()];
let completed = None;
Self {
size,
values,
called,
completed,
}
}
fn play(&mut self, num: &u8) -> Result<bool> {
if self.completed.is_some() {
return Ok(false);
}
for y in 0..self.size {
for x in 0..self.size {
let value = self.values.get(y * self.size + x)
.ok_or(anyhow!("Invalid BingoBoard"))?;
if value == num {
self.called[y * self.size + x] = true;
}
}
}
for y in 0..self.size {
let mut count = 0;
for x in 0..self.size {
if *self.called.get(y * self.size + x).ok_or(anyhow!("Invalid BingoBoard"))? {
count += 1;
}
if count == self.size {
self.completed = Some(*num);
return Ok(true);
}
}
}
for x in 0..self.size {
let mut count = 0;
for y in 0..self.size {
if *self.called.get(y * self.size + x).ok_or(anyhow!("Invalid BingoBoard"))? {
count += 1;
}
if count == self.size {
self.completed = Some(*num);
return Ok(true);
}
}
}
Ok(false)
}
fn sum_unmarked(&self) -> Result<usize> {
let mut sum = 0;
for y in 0..self.size {
for x in 0..self.size {
let value = self.values.get(y * self.size + x)
.ok_or(anyhow!("Invalid BingoBoard"))?;
if ! *self.called.get(y * self.size + x).ok_or(anyhow!("Invalid BingoBoard"))? {
sum += *value as usize;
}
}
}
Ok(sum)
}
}
impl Display for BingoBoard {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let mut s = String::new();
for y in 0..self.size {
for x in 0..self.size {
let value = self.values.get(y * self.size + x).ok_or(std::fmt::Error)?;
if *self.called.get(y * self.size + x).ok_or(std::fmt::Error)? {
s += &format!("[{:2}] ", value);
} else {
s += &format!(" {:2} ", value);
}
}
s += "\n";
}
if let Some(won) = self.completed {
s += &format!("Winning number: {}\n", won);
}
write!(f, "{}", s)
}
}
#[derive(Clone)]
struct BingoGame {
numbers: Vec<u8>,
boards: Vec<BingoBoard>,
}
impl BingoGame {
fn new() -> Self {
Self {
numbers: vec![],
boards: vec![],
}
}
}
fn read_input<T: AsRef<Path>>(filename: T) -> Result<BingoGame> {
let reader = BufReader::new(File::open(filename)?);
let mut game = BingoGame::new();
let mut boards: Vec<BingoBoard> = vec![];
let mut lines = reader.lines();
let draw_line = lines.next().ok_or(anyhow!("Could not parse draw_line"))?
.map_err(|err| anyhow!("{}", err))?;
let mut buffer: Vec<u8> = vec![];
for line in lines {
let l = line?;
if l.is_empty() {
if ! buffer.is_empty() {
let board = BingoBoard::new(&buffer);
boards.push(board);
}
buffer = vec![];
} else {
buffer.append(&mut l.split_whitespace().map(|v| v.parse()
.map_err(|_| anyhow!("Parse error"))).collect::<Result<_>>()?);
}
}
let board = BingoBoard::new(&buffer);
boards.push(board);
game.numbers = draw_line.split(',').map(|v| v.parse().map_err(|err| anyhow!("{}", err)))
.collect::<Result<_>>()?;
game.boards = boards;
Ok(game)
}
fn part1(game: &BingoGame) -> Result<usize> {
let mut game_mut = game.clone();
for num in &game_mut.numbers {
for board in &mut game_mut.boards {
if board.play(num)? {
// println!("{}", board);
return Ok(board.sum_unmarked()? * *num as usize);
}
}
}
Err(anyhow!("No winner"))
}
fn part2(game: &BingoGame) -> Result<usize> {
let mut game_mut = game.clone();
let mut last_winner = None;
for num in &game_mut.numbers {
for (index, board) in &mut game_mut.boards.iter_mut().enumerate() {
if board.play(num)? {
last_winner = Some(index);
}
}
}
if let Some(winner) = last_winner {
let board = &game_mut.boards[winner];
let unmarked_sum = board.sum_unmarked()?;
let won = board.completed.ok_or(anyhow!("No winning number"))? as usize;
// println!("Winning board: {} ({} * {})", winner + 1, unmarked_sum, won);
// println!("{}", board);
Ok(unmarked_sum * won)
} else {
Err(anyhow!("No winner"))
}
}
fn main() -> Result<()> {
let ( do_part_1, do_part_2 ) = aoc::do_parts();
let filename = args().nth(1).ok_or(anyhow!("Missing input filename"))?;
let input = read_input(filename).context("Could not read input")?;
if do_part_1 {
let solution = part1(&input).context("No solution for part 1")?;
println!("Part1, solution found to be: {}", solution);
}
if do_part_2 {
let solution = part2(&input).context("No solution for part 2")?;
println!("Part2, solution found to be: {}", solution);
}
Ok(())
}
|
