aoc_2024/Cargo.lock

@@ -11,12 +11,6 @@ dependencies = [
  "memchr",
 ]
 
-[[package]]
-name = "allocator-api2"
-version = "0.2.21"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "683d7910e743518b0e34f1186f92494becacb047c7b6bf616c96772180fef923"
-
 [[package]]
 name = "aoc-runner"
 version = "0.3.0"
@@ -52,7 +46,6 @@ version = "0.1.0"
 dependencies = [
  "aoc-runner",
  "aoc-runner-derive",
- "hashbrown",
  "nom",
  "num",
  "regex",
@@ -65,29 +58,6 @@ version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ace50bade8e6234aa140d9a2f552bbee1db4d353f69b8217bc503490fc1a9f26"
 
-[[package]]
-name = "equivalent"
-version = "1.0.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5443807d6dff69373d433ab9ef5378ad8df50ca6298caf15de6e52e24aaf54d5"
-
-[[package]]
-name = "foldhash"
-version = "0.1.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f81ec6369c545a7d40e4589b5597581fa1c441fe1cce96dd1de43159910a36a2"
-
-[[package]]
-name = "hashbrown"
-version = "0.15.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bf151400ff0baff5465007dd2f3e717f3fe502074ca563069ce3a6629d07b289"
-dependencies = [
- "allocator-api2",
- "equivalent",
- "foldhash",
-]
-
 [[package]]
 name = "itoa"
 version = "1.0.14"

aoc_2024/Cargo.toml

@@ -6,7 +6,6 @@ edition = "2021"
 [dependencies]
 aoc-runner = "0.3.0"
 aoc-runner-derive = "0.3.0"
-hashbrown = "0.15.2"
 nom = "7.1.3"
 num = "0.4.3"
 regex = "1.11.1"

aoc_2024/src/day8.rs

@@ -1,4 +1,4 @@
-use hashbrown::{HashMap, HashSet};
+use std::collections::{HashMap, HashSet};
 
 use aoc_runner_derive::{aoc, aoc_generator};
 use num::integer::gcd;
@@ -15,9 +15,11 @@ fn parse(input: &str) -> Input {
             .enumerate()
             .filter(|(_, c)| c != &'.')
             .for_each(|(x, c)| {
-                map.entry(c)
+                if let std::collections::hash_map::Entry::Vacant(e) = map.entry(c) {
-                    .or_insert(Vec::new())
+                    e.insert(vec![(x as isize, y as isize)]);
-                    .push((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();
@@ -48,7 +50,7 @@ fn part1(input: &Input) -> usize {
 
 #[aoc(day8, part2)]
 fn part2(input: &Input) -> usize {
-    let mut set = HashSet::with_capacity(input.1.len() * input.1.len());
+    let mut set = HashSet::new();
     input.1.iter().for_each(|vec| {
         for l in 0..vec.len() {
             for r in l + 1..vec.len() {
@@ -56,6 +58,7 @@ fn part2(input: &Input) -> usize {
                 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);
@@ -66,7 +69,7 @@ fn part2(input: &Input) -> usize {
                         break;
                     }
                 }
-                let mut d = -1;
+                let mut d = 0;
                 loop {
                     let c = (s.0 + d * v.0, s.1 + d * v.1);
                     d -= 1;
@@ -79,6 +82,12 @@ fn part2(input: &Input) -> usize {
             }
         }
     });
+    // for y in 0..input.0 .1 {
+    //     println!();
+    //     for x in 0..input.0 .0 {
+    //         print!("{}", if set.contains(&(x, y)) { '#' } else { '.' })
+    //     }
+    // }
     set.len()
 }
 
@@ -104,7 +113,5 @@ mod tests {
             )),
             34
         );
-
-        assert_eq!(part2(&parse(include_str!("../input/2024/day8.txt"))), 1017);
     }
 }