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|
use nom::{
character::complete::{line_ending, one_of},
combinator::map_res,
multi::{many1, separated_list1},
IResult,
};
use std::fs;
fn main() -> Result<(), Box<dyn std::error::Error>> {
let input = fs::read_to_string("inputs/day_11.txt")?;
let squid_grid = parse_squid_grid(&input).unwrap().1;
{
let mut squid_grid = squid_grid.clone();
let mut flashes_on_100 = 0;
for _ in 0..100 {
flashes_on_100 += squid_grid.flash();
}
dbg!(flashes_on_100);
}
{
let mut squid_grid = squid_grid.clone();
let sync_time = std::iter::repeat_with(|| squid_grid.flash())
.position(|flashes| flashes == 100)
.map(|x| x + 1);
dbg!(sync_time);
}
Ok(())
}
#[derive(Debug, Clone)]
struct Squid {
energy: u8,
has_flashed: bool,
}
impl Squid {
fn should_flash(&self) -> bool {
self.energy > 9 && !self.has_flashed
}
fn reset(&mut self) {
self.energy = 0;
self.has_flashed = false;
}
}
#[derive(Debug, Clone)]
struct SquidGrid {
squids: [[Squid; 10]; 10],
}
impl SquidGrid {
fn flash(&mut self) -> usize {
for y in 0..10 {
for x in 0..10 {
self.squids[y][x].energy += 1;
}
}
let mut any_new_flashes = true;
while any_new_flashes {
any_new_flashes = false;
for y in 0..10 {
for x in 0..10 {
if self.squids[y][x].should_flash() {
any_new_flashes = true;
self.squids[y][x].has_flashed = true;
if y > 0 && x > 0 {
self.squids[y - 1][x - 1].energy += 1;
}
if y > 0 {
self.squids[y - 1][x].energy += 1;
}
if y > 0 && x < 9 {
self.squids[y - 1][x + 1].energy += 1;
}
if x > 0 {
self.squids[y][x - 1].energy += 1;
}
if x < 9 {
self.squids[y][x + 1].energy += 1;
}
if y < 9 && x > 0 {
self.squids[y + 1][x - 1].energy += 1;
}
if y < 9 {
self.squids[y + 1][x].energy += 1;
}
if y < 9 && x < 9 {
self.squids[y + 1][x + 1].energy += 1;
}
}
}
}
}
let mut flashes = 0;
for y in 0..10 {
for x in 0..10 {
if self.squids[y][x].has_flashed {
self.squids[y][x].reset();
flashes += 1;
}
}
}
flashes
}
}
fn parse_squid_grid(input: &str) -> IResult<&str, SquidGrid> {
map_res(separated_list1(line_ending, parse_squid_row), |squids| {
squids.try_into().map(|squids| SquidGrid { squids })
})(input)
}
fn parse_squid_row(input: &str) -> IResult<&str, [Squid; 10]> {
map_res(many1(parse_squid), |squids| squids.try_into())(input)
}
fn parse_squid(input: &str) -> IResult<&str, Squid> {
map_res(one_of("0123456789"), |digit| {
digit.to_string().parse().map(|energy| Squid {
energy,
has_flashed: false,
})
})(input)
}
|
