Day 16

Author: prevostc

README.md

@@ -26,9 +26,9 @@ Solutions for [Advent of Code](https://adventofcode.com/) in [Rust](https://www.
 | [Day 13](./src/bin/13.rs) | `90.9µs` | `91.8µs` |
 | [Day 14](./src/bin/14.rs) | `30.8µs` | `3.5ms` |
 | [Day 15](./src/bin/15.rs) | `119.7µs` | `591.0µs` |
-| [Day 16](./src/bin/16.rs) | `203.4µs` | `33.3ms` |
+| [Day 16](./src/bin/16.rs) | `193.4µs` | `22.6ms` |
 
-**Total: 64.83ms**
+**Total: 54.12ms**
 <!--- benchmarking table --->
 
 ---

src/bin/16.rs

@@ -103,7 +103,7 @@ pub fn part_two(input: &str) -> Option<u64> {
         cost: u64,
     }
 
-    const PATH_CAPACITY: usize = 256;
+    const PATH_CAPACITY: usize = 512;
     let path_pool = Pool::new(256, || Vec::with_capacity(PATH_CAPACITY));
     let mut path = path_pool.pull(|| Vec::with_capacity(PATH_CAPACITY));
     path.push(start);
@@ -191,8 +191,7 @@ pub fn part_two(input: &str) -> Option<u64> {
 
                     let (pos, dir, cost) = all_options[idx];
                     let mut new_path = path_pool.pull(|| Vec::with_capacity(PATH_CAPACITY));
-                    new_path.clear();
-                    new_path.extend(s.path.iter());
+                    new_path.clone_from(&s.path);
                     new_path.push(pos);
                     let new_state = State {
                         path: new_path,