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use regex::Regex;
use std::collections::HashSet;
fn cycle_add(u: u32, i: i32, limit: u32) -> u32 {
let sum: i32 = u as i32 + i;
let mut sum_u: u32 = if sum < 0 { sum + limit as i32 } else { sum } as u32;
while sum_u >= limit {
sum_u -= limit;
}
sum_u
}
#[derive(Debug)]
struct Robot {
p: (u32, u32),
v: (i32, i32),
}
impl Robot {
fn parse(input: &str) -> Vec<Self> {
let mut result: Vec<_> = vec![];
let re = Regex::new(r"p=([0-9]+),([0-9]+) v=([0-9-]+),([0-9-]+)").unwrap();
for (_, [px, py, vx, vy]) in re.captures_iter(input).map(|c| c.extract()) {
result.push(Robot {
p: (px.parse().unwrap(), py.parse().unwrap()),
v: (vx.parse().unwrap(), vy.parse().unwrap()),
});
}
// println!("Result: {result:?}");
result
}
fn step(&mut self, (lx, ly): (u32, u32)) {
let p: &mut (u32, u32) = &mut self.p;
let v = self.v;
p.0 = cycle_add(p.0, v.0, lx);
p.1 = cycle_add(p.1, v.1, ly);
}
}
struct Bathroom {
robots: Vec<Robot>,
limit: (u32, u32),
}
impl Bathroom {
fn step(&mut self) {
for r in self.robots.iter_mut() {
r.step(self.limit);
}
}
fn stepn(&mut self, seconds: u32) {
for _i in 0..seconds {
self.step();
}
}
fn quadrant(&self, Robot { p: (px, py), .. }: &Robot) -> Option<usize> {
let (lx, ly) = self.limit;
let (hx, hy) = (lx / 2, ly / 2);
if *px == hx || *py == hy {
None
} else {
Some(if *px < hx { 0 } else { 1 } + if *py < hy { 0 } else { 2 })
}
}
fn safety(&self) -> u32 {
let mut scores = [0; 4];
for r in self.robots.iter() {
if let Some(q) = self.quadrant(r) {
scores[q] += 1;
}
}
scores.iter().product()
}
fn show(&self) {
let positions: HashSet<(u32, u32)> = self.robots.iter().map(|r| r.p).collect();
for i in 0..self.limit.1 {
for j in 0..self.limit.0 {
print!(
"{}",
if positions.contains(&(i, j)) {
"X"
} else {
"."
}
);
}
println!();
}
}
}
fn p1(input: &str) -> String {
let robots: Vec<Robot> = Robot::parse(input);
let mut bathroom: Bathroom = Bathroom {
robots,
limit: (101, 103),
};
bathroom.stepn(100);
dbg!(&bathroom.robots);
let result = bathroom.safety();
result.to_string()
}
// use std::thread::sleep;
// use std::time::Duration;
fn p2(input: &str) -> String {
let robots: Vec<Robot> = Robot::parse(input);
let mut bathroom: Bathroom = Bathroom {
robots,
limit: (101, 103),
};
bathroom.show();
for i in 1.. {
println!("\n\nAfter {} seconds:", i);
bathroom.step();
bathroom.show();
// sleep(Duration::from_millis(200));
}
unreachable!();
}
fn main() {
aoc2024::run_day("14", p1, p2);
}
|
