perf: optimize dijkstra all_paths using reference insteadof cloning

manhunto · Dec 23, 2024 · 8e0d3bb · 8e0d3bb
1 parent 205d3a1
commit 8e0d3bb
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Showing 2 changed files with 19 additions and 16 deletions.
diff --git a/readme.md b/readme.md
@@ -26,7 +26,7 @@
 | [Day 13: Claw Contraption](src/solutions/year2024/day13.rs)       |   ⭐⭐   |            0.241 |            0.331 |
 | [Day 14: Restroom Redoubt](src/solutions/year2024/day14.rs)       |   ⭐⭐   |            0.172 |          102.252 |
 | [Day 15: Warehouse Woes](src/solutions/year2024/day15.rs)         |   ⭐⭐   |            7.226 |            9.084 |
-| [Day 16: Reindeer Maze](src/solutions/year2024/day16.rs)          |   ⭐⭐   |            6.478 |           74.105 |
+| [Day 16: Reindeer Maze](src/solutions/year2024/day16.rs)          |   ⭐⭐   |            6.478 |           24.347 |
 | [Day 17: Chronospatial Computer](src/solutions/year2024/day17.rs) |   -    |                - |                - |
 | [Day 18: RAM Run](src/solutions/year2024/day18.rs)                |   ⭐⭐   |            2.487 |          204.885 |
 | [Day 19: Linen Layout](src/solutions/year2024/day19.rs)           |   ⭐⭐   |            2.923 |           22.751 |

diff --git a/src/utils/graphs/dijkstra.rs b/src/utils/graphs/dijkstra.rs
@@ -123,8 +123,8 @@ impl<'a, T> Dijkstra<'a, T> {
                 Self::visit(
                     start,
                     *end,
-                    Vec::new(),
-                    VecDeque::new(),
+                    &mut Vec::new(),
+                    &mut VecDeque::new(),
                     &mut paths,
                     come_from,
                 );
@@ -137,29 +137,32 @@ impl<'a, T> Dijkstra<'a, T> {
     fn visit(
         from: T,
         end: T,
-        mut visited: Vec<T>,
-        mut path: VecDeque<T>,
+        visited: &mut Vec<T>,
+        path: &mut VecDeque<T>,
         paths: &mut Vec<VecDeque<T>>,
         come_from: &HashMap<T, Vec<T>>,
     ) where
         T: Hash + Eq + PartialEq + Ord + Debug + Copy,
     {
-        {
-            visited.push(end);
-            path.push_front(end);
+        visited.push(end);
+        path.push_front(end);
 
-            if from == end {
-                paths.push(path.clone());
+        if from == end {
+            paths.push(path.clone());
+            path.pop_front();
+            visited.pop();
 
-                return;
-            }
+            return;
+        }
 
-            for p in come_from.get(&end).unwrap_or(&Vec::new()) {
-                if !visited.contains(p) {
-                    Self::visit(from, *p, visited.clone(), path.clone(), paths, come_from);
-                }
+        for p in come_from.get(&end).unwrap_or(&Vec::new()) {
+            if !visited.contains(p) {
+                Self::visit(from, *p, visited, path, paths, come_from);
             }
         }
+
+        path.pop_front();
+        visited.pop();
     }
 }