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#![allow(dead_code)]
#![allow(unused_variables)]
use advent_of_code::prelude::*;
fn dist(a: (Row, Col), b: (Row, Col)) -> usize {
a.0.abs_diff(b.0).0 + a.1.abs_diff(b.1).0
}
#[derive(Debug, Copy, Clone)]
struct Sensor {
pos: (Row, Col),
beacon: (Row, Col),
radius: usize,
}
impl Sensor {
fn new(pos: (Row, Col), beacon: (Row, Col)) -> Self {
Self {
pos,
beacon,
radius: dist(pos, beacon),
}
}
fn in_radius(&self, pos: (Row, Col)) -> bool {
dist(self.pos, pos) <= self.radius
}
}
pub struct Map {
sensors: Vec<Sensor>,
range_x: usize,
range_y: usize,
offset_x: usize,
offset_y: usize,
}
impl Map {
fn nearby_sensor(&self, pos: (Row, Col)) -> Option<Sensor> {
self.sensors
.iter()
.copied()
.find(|sensor| sensor.in_radius(pos))
}
}
pub fn parse(fh: File) -> Result<Map> {
let mut sensor_positions = vec![];
for line in parse::raw_lines(fh) {
let cap = regex_captures!(r"Sensor at x=(-?\d+), y=(-?\d+): closest beacon is at x=(-?\d+), y=(-?\d+)", &line)
.ok_or_else(|| anyhow::anyhow!("no match"))?;
let sensor_x: i64 = cap[1].parse()?;
let sensor_y: i64 = cap[2].parse()?;
let beacon_x: i64 = cap[3].parse()?;
let beacon_y: i64 = cap[4].parse()?;
sensor_positions.push((sensor_x, sensor_y, beacon_x, beacon_y));
}
let min_x = sensor_positions
.iter()
.map(|x| x.0)
.chain(sensor_positions.iter().map(|x| x.2))
.min()
.ok_or_else(|| anyhow::anyhow!("empty list"))?;
let min_y = sensor_positions
.iter()
.map(|x| x.1)
.chain(sensor_positions.iter().map(|x| x.3))
.min()
.ok_or_else(|| anyhow::anyhow!("empty list"))?;
let max_x = sensor_positions
.iter()
.map(|x| x.0)
.chain(sensor_positions.iter().map(|x| x.2))
.max()
.ok_or_else(|| anyhow::anyhow!("empty list"))?;
let max_y = sensor_positions
.iter()
.map(|x| x.1)
.chain(sensor_positions.iter().map(|x| x.3))
.max()
.ok_or_else(|| anyhow::anyhow!("empty list"))?;
let range_x = (max_x - min_x) as usize;
let range_y = (max_y - min_y) as usize;
let offset_x = -min_x as usize + range_x;
let offset_y = -min_y as usize + range_y;
let mut sensors = vec![];
for sensor in sensor_positions {
let pos = (
Row((sensor.1 + offset_y as i64) as usize),
Col((sensor.0 + offset_x as i64) as usize),
);
let beacon = (
Row((sensor.3 + offset_y as i64) as usize),
Col((sensor.2 + offset_x as i64) as usize),
);
sensors.push(Sensor::new(pos, beacon));
}
Ok(Map {
sensors,
range_x,
range_y,
offset_x,
offset_y,
})
}
pub fn part1(map: Map) -> Result<i64> {
let row = Row(2_000_000 + map.offset_y);
let mut total = 0;
for col in (0..(3 * map.range_x)).map(Col) {
if map.sensors.iter().any(|sensor| sensor.beacon == (row, col)) {
continue;
}
if map.nearby_sensor((row, col)).is_some() {
total += 1;
}
}
Ok(total)
}
pub fn part2(map: Map) -> Result<usize> {
for row in (0..=4_000_000).map(|r| Row(r + map.offset_y)) {
let mut col = Col(map.offset_x);
loop {
if let Some(sensor) = map.nearby_sensor((row, col)) {
let row_radius = sensor.radius - sensor.pos.0.abs_diff(row).0;
col = sensor.pos.1 + row_radius + 1;
if col > Col(4_000_000 + map.offset_x) {
break;
}
} else {
return Ok((col.0 - map.offset_x) * 4_000_000
+ (row.0 - map.offset_y));
}
}
}
Ok(0)
}
#[test]
fn test() {
assert_eq!(
part1(parse(parse::data(2022, 15).unwrap()).unwrap()).unwrap(),
4737443
);
assert_eq!(
part2(parse(parse::data(2022, 15).unwrap()).unwrap()).unwrap(),
11482462818989
);
}
|
