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|
use std::fs;
use std::fmt;
use std::path::Path;
struct Bingo {
cards: Vec<BingoCard>
}
impl Bingo {
fn update(&mut self, draw: u32) -> Vec<(usize,u32)> {
self.cards.iter_mut().enumerate().filter_map(
|(i,c)| {
if let Some(s) = c.mark(draw) {
if c.ingame { return Some((i,s)) }
}
None
}
).collect()
}
fn simulate(&mut self, draws: &[u32]) -> u32 {
if draws.len() > 0 {
if let Some((_,score)) = self.update(draws[0]).first() {
*score
} else {
self.simulate(&draws[1..])
}
} else {
unreachable!()
}
}
fn simulate_all(&mut self, draws: &[u32]) -> u32 {
if draws.len() > 0 {
for (index,score) in self.update(draws[0]) {
if self.cards.iter().filter(|c| c.ingame).count() == 1 {
return score
}
self.cards[index].ingame = false;
}
self.simulate_all(&draws[1..])
} else {
unreachable!()
}
}
}
#[derive(Clone)]
struct BingoCard {
ingame: bool,
nums: Vec<(u32,bool)>
}
impl BingoCard {
fn mark(&mut self, n: u32) -> Option<u32> {
if let Some(pos) = self.nums.iter().position(|c| c.0 == n) {
self.nums[pos].1 = true;
if self.check(pos) {
Some(self.score() * n)
} else { None }
} else { None }
}
fn check(&self, pos: usize) -> bool {
let row = pos / 5;
let col = pos % 5;
(5*row..5*row+5).all(|c| self.nums[c].1)
|| (0usize..5).all(|c| self.nums[c*5+col].1)
}
fn score(&self) -> u32 {
self.nums.iter().filter_map(|c| if c.1 { None } else { Some(c.0) }).sum()
}
}
impl fmt::Display for BingoCard {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let str = self.nums.iter().enumerate().map(
|(n,c)| format!("{:>2}{}{}", c.0, if c.1 { '*' } else { ' ' }, if (n+1)%5 == 0 { '\n' } else { ' ' })
).collect::<Vec<String>>().join("");
write!(f, "{}", str)
}
}
impl From<&str> for BingoCard {
fn from(s: &str) -> Self {
let mut nums = Vec::with_capacity(25);
s.lines().for_each(
|l| l.split_whitespace().for_each(
|n| nums.push((n.parse().expect("Malformed input"), false))
)
);
BingoCard { ingame: true, nums }
}
}
/* AOC21 Day 4: https://adventofcode.com/2021/day/4 */
fn main() {
let input = Path::new("resources").join("input.txt");
let content = fs::read_to_string(input).expect("Unable to read input file");
let report: Vec<&str> = content.split("\n\n").collect();
let draws: Vec<u32> = report[0].split(",").map(|x| x.parse().expect("Malformed input")).collect();
let cards: Vec<BingoCard> = report[1..].iter().map(|&c| BingoCard::from(c)).collect();
println!("Ex1: The result is {}", Bingo { cards: cards.clone() }.simulate(&draws));
println!("Ex1: The result is {}", Bingo { cards }.simulate_all(&draws));
}
#[cfg(test)]
mod tests {
use super::*;
const 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
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";
#[test]
fn winning_score() {
let report: Vec<&str> = INPUT.split("\n\n").collect();
let draws: Vec<u32> = report[0].split(",").map(|x| x.parse().expect("Malformed input")).collect();
let cards: Vec<BingoCard> = report[1..].iter().map(|&c| BingoCard::from(c)).collect();
assert_eq!(4512, Bingo { cards }.simulate(&draws))
}
#[test]
fn last_winning_score() {
let report: Vec<&str> = INPUT.split("\n\n").collect();
let draws: Vec<u32> = report[0].split(",").map(|x| x.parse().expect("Malformed input")).collect();
let cards: Vec<BingoCard> = report[1..].iter().map(|&c| BingoCard::from(c)).collect();
assert_eq!(1924, Bingo { cards }.simulate_all(&draws))
}
}
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