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|
use std::collections::HashSet;
fn main() {
let input = advent::read_all_lines(4);
println!("4a: {}", find_winning_score(&input));
println!("4b: {}", find_losing_score(&input));
}
#[derive(PartialEq, Eq, Hash, Clone)]
struct Bingo {
board: Vec<Vec<Option<u32>>>,
original_board: Vec<Vec<Option<u32>>>,
}
impl Bingo {
const BOARD_SIZE: usize = 5;
fn new<T: AsRef<str>>(input: &[T]) -> Bingo {
let mut board = Vec::new();
for line in input {
let line : Vec<Option<u32>> = line.as_ref().split(' ')
.filter(|n| !n.is_empty())
.map(|n| n.parse::<u32>().ok())
.collect();
board.push(line)
}
Bingo { board: board.clone(), original_board: board }
}
fn has_bingo(&self) -> bool {
for line in &self.board {
let hits = line.iter()
.filter(|n| n.is_none())
.count();
if hits == Bingo::BOARD_SIZE {
return true;
}
}
for i in 0 .. Bingo::BOARD_SIZE {
let hits = self.board.iter()
.filter(|line| line[i].is_none())
.count();
if hits == Bingo::BOARD_SIZE {
return true;
}
}
false
}
fn draw_number(&mut self, drawn: u32) {
for line in 0 .. Bingo::BOARD_SIZE {
for column in 0 .. Bingo::BOARD_SIZE {
if self.board[line][column] == Some(drawn) {
self.board[line][column] = None;
}
}
}
}
fn score(&self) -> u32 {
self.board.iter()
.flatten()
.flatten()
.sum()
}
}
fn parse_boards<T: AsRef<str>>(input: &[T]) -> Vec<Bingo> {
let mut boards = Vec::new();
for i in 0 .. input.len() / (Bingo::BOARD_SIZE + 1) {
let start = i * (Bingo::BOARD_SIZE + 1) + 1;
let end = start + Bingo::BOARD_SIZE;
let board = Bingo::new(&input[start .. end]);
boards.push(board);
}
boards
}
fn find_winning_score<T: AsRef<str>>(input: &[T]) -> u32 {
find_score(input, false)
}
fn find_losing_score<T: AsRef<str>>(input: &[T]) -> u32 {
find_score(input, true)
}
fn find_score<T: AsRef<str>>(input: &[T], wins_last: bool) -> u32 {
let numbers : Vec<u32> = input[0].as_ref()
.split(',')
.map(|n| n.parse::<u32>().unwrap())
.collect();
let mut boards = parse_boards(&input[1..]);
let board_count = boards.len();
let mut solved_boards = HashSet::new();
for number in numbers {
for board in &mut boards {
board.draw_number(number);
if board.has_bingo() {
if !wins_last {
return board.score() * number;
}
solved_boards.insert(board.original_board.clone());
if solved_boards.len() == board_count {
return board.score() * number;
}
}
}
}
panic!("No board with bingo found");
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test() {
let input = [
"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",
"",
"22 13 17 11 0",
" 8 2 23 4 24",
"21 9 14 16 7",
" 6 10 3 18 5",
" 1 12 20 15 19",
"",
" 3 15 0 2 22",
" 9 18 13 17 5",
"19 8 7 25 23",
"20 11 10 24 4",
"14 21 16 12 6",
"",
"14 21 17 24 4",
"10 16 15 9 19",
"18 8 23 26 20",
"22 11 13 6 5",
" 2 0 12 3 7",
];
assert_eq!(find_winning_score(&input), 4512);
assert_eq!(find_losing_score(&input), 1924);
}
}
|
