day8

aoc_2024/Cargo.lock

@@ -47,10 +47,17 @@ dependencies = [
  "aoc-runner",
  "aoc-runner-derive",
  "nom",
+ "num",
  "regex",
  "topological-sort",
 ]
 
+[[package]]
+name = "autocfg"
+version = "1.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ace50bade8e6234aa140d9a2f552bbee1db4d353f69b8217bc503490fc1a9f26"
+
 [[package]]
 name = "itoa"
 version = "1.0.14"
@@ -79,6 +86,79 @@ dependencies = [
  "minimal-lexical",
 ]
 
+[[package]]
+name = "num"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "35bd024e8b2ff75562e5f34e7f4905839deb4b22955ef5e73d2fea1b9813cb23"
+dependencies = [
+ "num-bigint",
+ "num-complex",
+ "num-integer",
+ "num-iter",
+ "num-rational",
+ "num-traits",
+]
+
+[[package]]
+name = "num-bigint"
+version = "0.4.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a5e44f723f1133c9deac646763579fdb3ac745e418f2a7af9cd0c431da1f20b9"
+dependencies = [
+ "num-integer",
+ "num-traits",
+]
+
+[[package]]
+name = "num-complex"
+version = "0.4.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "73f88a1307638156682bada9d7604135552957b7818057dcef22705b4d509495"
+dependencies = [
+ "num-traits",
+]
+
+[[package]]
+name = "num-integer"
+version = "0.1.46"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7969661fd2958a5cb096e56c8e1ad0444ac2bbcd0061bd28660485a44879858f"
+dependencies = [
+ "num-traits",
+]
+
+[[package]]
+name = "num-iter"
+version = "0.1.45"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1429034a0490724d0075ebb2bc9e875d6503c3cf69e235a8941aa757d83ef5bf"
+dependencies = [
+ "autocfg",
+ "num-integer",
+ "num-traits",
+]
+
+[[package]]
+name = "num-rational"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f83d14da390562dca69fc84082e73e548e1ad308d24accdedd2720017cb37824"
+dependencies = [
+ "num-bigint",
+ "num-integer",
+ "num-traits",
+]
+
+[[package]]
+name = "num-traits"
+version = "0.2.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "071dfc062690e90b734c0b2273ce72ad0ffa95f0c74596bc250dcfd960262841"
+dependencies = [
+ "autocfg",
+]
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.92"

aoc_2024/Cargo.toml

@@ -7,5 +7,6 @@ edition = "2021"
 aoc-runner = "0.3.0"
 aoc-runner-derive = "0.3.0"
 nom = "7.1.3"
+num = "0.4.3"
 regex = "1.11.1"
 topological-sort = "0.2.2"

aoc_2024/src/day3.rs

@@ -52,6 +52,10 @@ mod tests {
             )),
             161
         );
+        assert_eq!(
+            part1(&parse(include_str!("../input/2024/day3.txt"))),
+            191183308
+        );
     }
 
     #[test]
@@ -62,5 +66,9 @@ mod tests {
             )),
             48
         );
+        assert_eq!(
+            part2(&parse(include_str!("../input/2024/day3.txt"))),
+            92082041
+        );
     }
 }

aoc_2024/src/day8.rs

@@ -0,0 +1,117 @@
+use std::collections::{HashMap, HashSet};
+
+use aoc_runner_derive::{aoc, aoc_generator};
+use num::integer::gcd;
+
+type Input = ((isize, isize), Vec<Vec<(isize, isize)>>);
+
+#[aoc_generator(day8)]
+fn parse(input: &str) -> Input {
+    let mut map = HashMap::new();
+    let h = input.lines().count();
+    let w = input.lines().find(|_| true).unwrap().len();
+    input.lines().enumerate().for_each(|(y, line)| {
+        line.chars()
+            .enumerate()
+            .filter(|(_, c)| c != &'.')
+            .for_each(|(x, c)| {
+                if let std::collections::hash_map::Entry::Vacant(e) = map.entry(c) {
+                    e.insert(vec![(x as isize, y as isize)]);
+                } else {
+                    map.get_mut(&c).unwrap().push((x as isize, y as isize));
+                }
+            });
+    });
+    let vec = map.into_values().collect();
+    ((w as isize, h as isize), vec)
+}
+
+#[aoc(day8, part1)]
+fn part1(input: &Input) -> usize {
+    let mut set = HashSet::new();
+    input.1.iter().for_each(|vec| {
+        for l in 0..vec.len() {
+            for r in l + 1..vec.len() {
+                let a1 = vec[l];
+                let a2 = vec[r];
+                let c1 = (2 * a1.0 - a2.0, 2 * a1.1 - a2.1);
+                let c2 = (2 * a2.0 - a1.0, 2 * a2.1 - a1.1);
+                if c1.0 >= 0 && c1.0 < input.0 .0 && c1.1 >= 0 && c1.1 < input.0 .1 {
+                    set.insert(c1);
+                }
+                if c2.0 >= 0 && c2.0 < input.0 .0 && c2.1 >= 0 && c2.1 < input.0 .1 {
+                    set.insert(c2);
+                }
+            }
+        }
+    });
+    set.len()
+}
+
+#[aoc(day8, part2)]
+fn part2(input: &Input) -> usize {
+    let mut set = HashSet::new();
+    input.1.iter().for_each(|vec| {
+        for l in 0..vec.len() {
+            for r in l + 1..vec.len() {
+                let a1 = vec[l];
+                let a2 = vec[r];
+                let s = a1;
+                let v = (a2.0 - a1.0, a2.1 - a1.1);
+                let v = (v.0 / gcd(v.0, v.1), v.1 / gcd(v.0, v.1));
+                let mut d = 0;
+                loop {
+                    let c = (s.0 + d * v.0, s.1 + d * v.1);
+                    d += 1;
+                    if c.0 >= 0 && c.0 < input.0 .0 && c.1 >= 0 && c.1 < input.0 .1 {
+                        set.insert(c);
+                    } else {
+                        break;
+                    }
+                }
+                let mut d = 0;
+                loop {
+                    let c = (s.0 + d * v.0, s.1 + d * v.1);
+                    d -= 1;
+                    if c.0 >= 0 && c.0 < input.0 .0 && c.1 >= 0 && c.1 < input.0 .1 {
+                        set.insert(c);
+                    } else {
+                        break;
+                    }
+                }
+            }
+        }
+    });
+    // for y in 0..input.0 .1 {
+    //     println!();
+    //     for x in 0..input.0 .0 {
+    //         print!("{}", if set.contains(&(x, y)) { '#' } else { '.' })
+    //     }
+    // }
+    set.len()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn part1_example() {
+        assert_eq!(
+            part1(&parse(
+                "............\n........0...\n.....0......\n.......0....\n....0.......\n......A.....\n............\n............\n........A...\n.........A..\n............\n............"
+            )),
+            14
+        );
+    }
+
+    #[test]
+    fn part2_example() {
+        assert_eq!(
+            part2(&parse(
+                "............\n........0...\n.....0......\n.......0....\n....0.......\n......A.....\n............\n............\n........A...\n.........A..\n............\n............"
+            )),
+            34
+        );
+    }
+}

aoc_2024/src/lib.rs

@@ -1,3 +1,4 @@
+mod day8;
 mod day1;
 mod day2;
 mod day3;