119 lines
2.9 KiB
Rust
119 lines
2.9 KiB
Rust
use std::error::Error;
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use std::fs::File;
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use std::io::{self, BufRead};
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use std::vec::Vec;
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struct Board {
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numbers: Vec<Vec<i32>>,
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marked: Vec<Vec<bool>>,
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}
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impl Board {
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fn from_lines(lines: &mut impl Iterator<Item = String>) -> Option<Board> {
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let mut numbers = Vec::new();
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let mut marked = Vec::new();
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while let Some(line) = lines.next() {
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if line == "" {
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break;
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}
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let row: Vec<i32> = line
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.split(" ")
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.filter(|n| n.len() != 0)
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.map(|n| n.parse().unwrap())
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.collect();
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let mut markers: Vec<bool> = Vec::new();
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markers.resize(row.len(), false);
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numbers.push(row);
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marked.push(markers);
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}
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if numbers.len() != 0 {
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Some(Board { numbers, marked })
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} else {
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None
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}
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}
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fn mark(&mut self, num: i32) {
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for y in 0..self.numbers.len() {
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for x in 0..self.numbers[y].len() {
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if self.numbers[y][x] == num {
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self.marked[y][x] = true;
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}
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}
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}
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}
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fn has_won(&self) -> bool {
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if self.marked.iter().any(|r| r.iter().all(|m| *m)) {
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return true;
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}
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for x in 0..self.marked[0].len() {
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let mut col = true;
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for y in 0..self.marked.len() {
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col = col && self.marked[y][x];
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}
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if col {
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return true;
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}
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}
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false
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}
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fn sum_unmarked(&self) -> i32 {
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let mut sum = 0;
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for y in 0..self.numbers.len() {
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for x in 0..self.numbers[y].len() {
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if !self.marked[y][x] {
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sum += self.numbers[y][x];
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}
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}
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}
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sum
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}
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}
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fn main() -> Result<(), Box<dyn Error>> {
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let file = File::open("inputs/day4.txt")?;
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let mut lines = io::BufReader::new(file).lines().map(|l| l.unwrap());
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let numbers_drawn: Vec<i32> = lines
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.next()
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.unwrap()
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.split(",")
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.map(|n| n.parse().unwrap())
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.collect();
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lines.next();
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let mut boards: Vec<Board> = Vec::new();
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while let Some(board) = Board::from_lines(&mut lines) {
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boards.push(board);
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}
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let mut points_first: Option<i32> = None;
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let mut points_last = 0;
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for number in numbers_drawn {
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for board in boards.iter_mut() {
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if !board.has_won() {
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board.mark(number);
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if board.has_won() {
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points_last = board.sum_unmarked() * number;
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if points_first.is_none() {
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points_first = Some(points_last);
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}
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}
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}
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}
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}
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println!("Answer1: {}", points_first.unwrap());
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println!("Answer2: {}", points_last);
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Ok(())
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}
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