Day 22 part 1

2021/src/day22.rs

@@ -0,0 +1,144 @@
+use advent::prelude::*;
+use aoc_runner_derive::aoc;
+
+#[derive(Debug)]
+struct Instruction {
+    on: bool,
+    x_rng: RangeInclusive<i64>,
+    y_rng: RangeInclusive<i64>,
+    z_rng: RangeInclusive<i64>,
+}
+
+impl FromStr for Instruction {
+    type Err = Infallible;
+
+    fn from_str(input: &str) -> std::result::Result<Instruction, Infallible> {
+        // on x=11..13,y=11..13,z=11..13
+        // off x=9..11,y=9..11,z=9..11
+        let (verb, rest) = input.split_once(' ').unwrap();
+        let on = match verb {
+            "on" => true,
+            "off" => false,
+            _ => unreachable!("unexpected instruction type"),
+        };
+
+        let parts: Vec<_> = rest.split(',').collect();
+        let parse_rng = |s: &str| -> RangeInclusive<i64> {
+            s.split_once('=')
+                .unwrap()
+                .1
+                .split_once("..")
+                .map(|(lo, hi)| (lo.parse().unwrap(), hi.parse().unwrap()))
+                .map(|(lo, hi)| lo..=hi)
+                .unwrap()
+        };
+        let x_rng = parse_rng(parts[0]);
+        let y_rng = parse_rng(parts[1]);
+        let z_rng = parse_rng(parts[2]);
+        Ok(Instruction {
+            on,
+            x_rng,
+            y_rng,
+            z_rng,
+        })
+    }
+}
+
+fn part1_apply(insts: Vec<Instruction>) -> usize {
+    let mut grid = HashSet::new();
+    for inst in &insts {
+        dbg!(&inst);
+        for x in inst.x_rng.clone() {
+            for y in inst.y_rng.clone() {
+                for z in inst.z_rng.clone() {
+                    if inst.on {
+                        grid.insert((x, y, z));
+                    } else {
+                        grid.remove(&(x, y, z));
+                    }
+                }
+            }
+        }
+    }
+    grid.len()
+}
+
+fn inbounds(r: &RangeInclusive<i64>) -> bool {
+    // lazy but good enough for part1
+    r.start().abs() <= 50
+}
+
+#[aoc(day22, part1)]
+fn part1(input: &str) -> Result<usize> {
+    let insts: Vec<Instruction> = input
+        .lines()
+        .map(|l| l.parse().expect("failed to parse instruction"))
+        .filter(|i: &Instruction| inbounds(&i.x_rng) && inbounds(&i.y_rng) && inbounds(&i.z_rng))
+        .collect();
+    dbg!(&insts);
+    Ok(part1_apply(insts))
+}
+
+/*
+#[aoc(day22, part2)]
+fn part2(input: &str) -> Result<usize> {
+todo!("part2");
+Ok(0)
+}
+*/
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_part1() -> Result<()> {
+        let input = r#"
+        on x=10..12,y=10..12,z=10..12
+on x=11..13,y=11..13,z=11..13
+off x=9..11,y=9..11,z=9..11
+on x=10..10,y=10..10,z=10..10
+"#
+        .trim();
+        assert_eq!(part1(input)?, 39);
+
+        let input = r#"
+        on x=-20..26,y=-36..17,z=-47..7
+on x=-20..33,y=-21..23,z=-26..28
+on x=-22..28,y=-29..23,z=-38..16
+on x=-46..7,y=-6..46,z=-50..-1
+on x=-49..1,y=-3..46,z=-24..28
+on x=2..47,y=-22..22,z=-23..27
+on x=-27..23,y=-28..26,z=-21..29
+on x=-39..5,y=-6..47,z=-3..44
+on x=-30..21,y=-8..43,z=-13..34
+on x=-22..26,y=-27..20,z=-29..19
+off x=-48..-32,y=26..41,z=-47..-37
+on x=-12..35,y=6..50,z=-50..-2
+off x=-48..-32,y=-32..-16,z=-15..-5
+on x=-18..26,y=-33..15,z=-7..46
+off x=-40..-22,y=-38..-28,z=23..41
+on x=-16..35,y=-41..10,z=-47..6
+off x=-32..-23,y=11..30,z=-14..3
+on x=-49..-5,y=-3..45,z=-29..18
+off x=18..30,y=-20..-8,z=-3..13
+on x=-41..9,y=-7..43,z=-33..15
+on x=-54112..-39298,y=-85059..-49293,z=-27449..7877
+on x=967..23432,y=45373..81175,z=27513..53682
+"#
+        .trim();
+        assert_eq!(part1(input)?, 590784);
+        Ok(())
+    }
+
+    /*
+    #[test]
+    fn test_part2()->Result<()> {
+    let input = r#"
+    "#
+    .trim();
+    assert_eq!(part2(input)?, usize::MAX);
+    Ok(())
+    }
+    */
+}

2021/src/lib.rs

@@ -11,6 +11,7 @@ pub mod day17;
 pub mod day2;
 pub mod day20;
 pub mod day21;
+pub mod day22;
 pub mod day3;
 pub mod day4;
 pub mod day5;

src/lib.rs

@@ -5,7 +5,7 @@ pub mod prelude {
         fmt::{Debug, Display, Error, Formatter},
         io::Read,
         num::ParseIntError,
-        ops::{Index, IndexMut},
+        ops::{Index, IndexMut, RangeInclusive},
         str::FromStr,
     };