day 15 done (partial clippy)

day15/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "day15"
+version.workspace = true
+edition.workspace = true
+authors.workspace = true
+repository.workspace = true
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+nom.workspace = true
+itertools.workspace = true

day15/input.txt

@@ -0,0 +1,24 @@
+Sensor at x=3291456, y=3143280: closest beacon is at x=3008934, y=2768339
+Sensor at x=3807352, y=3409566: closest beacon is at x=3730410, y=3774311
+Sensor at x=1953670, y=1674873: closest beacon is at x=2528182, y=2000000
+Sensor at x=2820269, y=2810878: closest beacon is at x=2796608, y=2942369
+Sensor at x=3773264, y=3992829: closest beacon is at x=3730410, y=3774311
+Sensor at x=2913793, y=2629579: closest beacon is at x=3008934, y=2768339
+Sensor at x=1224826, y=2484735: closest beacon is at x=2528182, y=2000000
+Sensor at x=1866102, y=3047750: closest beacon is at x=1809319, y=3712572
+Sensor at x=3123635, y=118421: closest beacon is at x=1453587, y=-207584
+Sensor at x=2530789, y=2254773: closest beacon is at x=2528182, y=2000000
+Sensor at x=230755, y=3415342: closest beacon is at x=1809319, y=3712572
+Sensor at x=846048, y=51145: closest beacon is at x=1453587, y=-207584
+Sensor at x=3505756, y=3999126: closest beacon is at x=3730410, y=3774311
+Sensor at x=2506301, y=3745758: closest beacon is at x=1809319, y=3712572
+Sensor at x=1389843, y=957209: closest beacon is at x=1453587, y=-207584
+Sensor at x=3226352, y=3670258: closest beacon is at x=3730410, y=3774311
+Sensor at x=3902053, y=3680654: closest beacon is at x=3730410, y=3774311
+Sensor at x=2573020, y=3217129: closest beacon is at x=2796608, y=2942369
+Sensor at x=3976945, y=3871511: closest beacon is at x=3730410, y=3774311
+Sensor at x=107050, y=209321: closest beacon is at x=1453587, y=-207584
+Sensor at x=3931251, y=1787536: closest beacon is at x=2528182, y=2000000
+Sensor at x=1637093, y=3976664: closest beacon is at x=1809319, y=3712572
+Sensor at x=2881987, y=1923522: closest beacon is at x=2528182, y=2000000
+Sensor at x=3059723, y=2540501: closest beacon is at x=3008934, y=2768339

day15/src/main.rs

@@ -0,0 +1,266 @@
+#![warn(clippy::all, clippy::pedantic)]
+
+use std::{collections::BTreeMap, fmt::Display, fs, ops::RangeInclusive};
+
+use itertools::Itertools;
+use nom::{
+    bytes::complete::tag,
+    character::complete::{self, newline},
+    multi::separated_list1,
+};
+
+trait Pos {
+    fn get_pos(self) -> (i64, i64);
+}
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct Sensor {
+    pub x: i64,
+    pub y: i64,
+    pub strength: i64,
+}
+
+impl Sensor {
+    pub fn x_covereage_at_y(&self, y: i64) -> Option<RangeInclusive<i64>> {
+        let dist = (y - self.y).abs();
+        let n = self.strength - dist;
+        if n < 0 {
+            return None;
+        }
+        Some((self.x - n)..=(self.x + n))
+    }
+    pub fn coverage(&self) -> Vec<(i64, RangeInclusive<i64>)> {
+        ((self.y - self.strength)..=(self.y + self.strength))
+            .map(|y| {
+                let Some(x_s) = self.x_covereage_at_y(y) else {
+                    panic!()
+                };
+                (y, x_s)
+            })
+            .collect()
+    }
+}
+impl Pos for Sensor {
+    fn get_pos(self) -> (i64, i64) {
+        (self.x, self.y)
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct Beacon {
+    pub x: i64,
+    pub y: i64,
+}
+impl Pos for Beacon {
+    fn get_pos(self) -> (i64, i64) {
+        (self.x, self.y)
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub enum Square {
+    Covered,
+    Beacon(Beacon),
+    Sensor(Sensor),
+}
+impl Square {
+    pub fn is_covered(&self) -> bool {
+        matches!(self, Self::Covered)
+    }
+}
+impl Display for Square {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(
+            f,
+            "{}",
+            match self {
+                Self::Covered => '#',
+                Self::Beacon(_) => 'B',
+                Self::Sensor(_) => 'S',
+            }
+        )
+    }
+}
+impl From<&Sensor> for Square {
+    fn from(value: &Sensor) -> Self {
+        Self::Sensor(*value)
+    }
+}
+impl From<Sensor> for Square {
+    fn from(value: Sensor) -> Self {
+        Self::Sensor(value)
+    }
+}
+impl From<&Beacon> for Square {
+    fn from(value: &Beacon) -> Self {
+        Self::Beacon(*value)
+    }
+}
+impl From<Beacon> for Square {
+    fn from(value: Beacon) -> Self {
+        Self::Beacon(value)
+    }
+}
+
+fn parse_reading(input: &str) -> nom::IResult<&str, (Sensor, Beacon)> {
+    let (input, _) = tag("Sensor at x=")(input)?;
+    let (input, x_sensor) = complete::i64(input)?;
+    let (input, _) = tag(", y=")(input)?;
+    let (input, y_sensor) = complete::i64(input)?;
+    let (input, _) = tag(": closest beacon is at x=")(input)?;
+    let (input, x_beacon) = complete::i64(input)?;
+    let (input, _) = tag(", y=")(input)?;
+    let (input, y_beacon) = complete::i64(input)?;
+    let dist = (x_sensor - x_beacon).abs() + (y_sensor - y_beacon).abs();
+
+    Ok((
+        input,
+        (
+            Sensor {
+                x: x_sensor,
+                y: y_sensor,
+                strength: dist,
+            },
+            Beacon {
+                x: x_beacon,
+                y: y_beacon,
+            },
+        ),
+    ))
+}
+fn parse_output(input: &str) -> nom::IResult<&str, Vec<Square>> {
+    let (input, readings) = separated_list1(newline, parse_reading)(input)?;
+    let output = readings
+        .iter()
+        .flat_map(|(sensor, beacon)| vec![sensor.into(), beacon.into()])
+        .unique()
+        .collect();
+
+    Ok((input, output))
+}
+
+fn coverage_count_at_y(board: &[Square], y: i64) -> Vec<i64> {
+    board
+        .iter()
+        .filter_map(|square| match square {
+            Square::Sensor(sensor) => Some(sensor),
+            _ => None,
+        })
+        .filter_map(|sensor| sensor.x_covereage_at_y(y))
+        .flatten()
+        .unique()
+        .collect()
+}
+pub fn part1(board: &[Square], y: i64) -> String {
+    let pos_covered_on_y = coverage_count_at_y(board, y).len();
+    let obs_on_y = board
+        .iter()
+        .filter_map(|square| match square {
+            Square::Beacon(beacon) => {
+                if beacon.y == y {
+                    Some(beacon.x)
+                } else {
+                    None
+                }
+            }
+            Square::Sensor(sensor) => {
+                if sensor.y == y {
+                    Some(sensor.x)
+                } else {
+                    None
+                }
+            }
+            Square::Covered => None,
+        })
+        .unique()
+        .count();
+    (pos_covered_on_y - obs_on_y).to_string()
+}
+
+pub fn part2(board: &[Square], lower: i64, upper: i64) -> String {
+    let bb = board
+        .iter()
+        .filter_map(|square| match square {
+            Square::Sensor(x) => Some(x),
+            _ => None,
+        })
+        .flat_map(|square| {
+            square
+                .coverage()
+                .into_iter()
+                .filter(|(y, _)| y >= &lower && y <= &upper)
+                .map(|(y, x_s)| (y, *x_s.start().max(&lower)..=*x_s.end().min(&upper)))
+        })
+        .fold(BTreeMap::new(), |mut acc, (y, x_s)| {
+            acc.entry(y)
+                .and_modify(|x_range: &mut Vec<RangeInclusive<i64>>| x_range.push(x_s.clone()))
+                .or_insert(vec![x_s]);
+            acc
+        });
+    let (x, y) = bb
+        .into_iter()
+        .find_map(|(y, mut x_s)| {
+            x_s.sort_by(|a, b| a.start().cmp(b.start()));
+            x_s.iter()
+                .fold(
+                    (lower..=lower, None),
+                    |mut acc: (RangeInclusive<i64>, Option<i64>), x_range: &RangeInclusive<i64>| {
+                        if acc.1.is_some() {
+                            return acc;
+                        }
+                        if acc.0.end() + 1 >= *x_range.start() {
+                            acc.0 = *acc.0.start()..=*acc.0.end().max(x_range.end());
+                        } else {
+                            acc.1 = Some(acc.0.end() + 1);
+                        }
+                        acc
+                    },
+                )
+                .1
+                .map(|x| (x, y))
+        })
+        .unwrap();
+    (4_000_000 * x + y).to_string()
+}
+
+fn main() {
+    let file = fs::read_to_string("./input.txt").unwrap();
+    let (_, board) = parse_output(&file).unwrap();
+
+    let y = 2_000_000;
+
+    println!("Part 1: {}", part1(&board, y));
+
+    println!("Part 2: {}", part2(&board, 0, 4_000_000));
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    const INPUT: &str = "Sensor at x=2, y=18: closest beacon is at x=-2, y=15
+Sensor at x=9, y=16: closest beacon is at x=10, y=16
+Sensor at x=13, y=2: closest beacon is at x=15, y=3
+Sensor at x=12, y=14: closest beacon is at x=10, y=16
+Sensor at x=10, y=20: closest beacon is at x=10, y=16
+Sensor at x=14, y=17: closest beacon is at x=10, y=16
+Sensor at x=8, y=7: closest beacon is at x=2, y=10
+Sensor at x=2, y=0: closest beacon is at x=2, y=10
+Sensor at x=0, y=11: closest beacon is at x=2, y=10
+Sensor at x=20, y=14: closest beacon is at x=25, y=17
+Sensor at x=17, y=20: closest beacon is at x=21, y=22
+Sensor at x=16, y=7: closest beacon is at x=15, y=3
+Sensor at x=14, y=3: closest beacon is at x=15, y=3
+Sensor at x=20, y=1: closest beacon is at x=15, y=3";
+
+    #[test]
+    fn part1_works() {
+        let (_, board) = parse_output(INPUT).unwrap();
+        assert_eq!(part1(&board, 10), "26");
+    }
+
+    #[test]
+    fn part2_works() {
+        let (_, board) = parse_output(INPUT).unwrap();
+        assert_eq!(part2(&board, 0, 20), "56000011");
+    }
+}