removing the hashset

Author: frederictaillandier

src/bfs.rs

@@ -26,21 +26,20 @@ impl Graph {
 /// Naive BFS implementation using Vec as a queue (intentionally slow)
 /// Returns the order in which nodes were visited
 pub fn bfs_naive(graph: &Graph, start: usize) -> VecDeque<usize> {
-    let mut visited = HashSet::new();
-    let mut queue = VecDeque::with_capacity(256); // Using Vec instead of VecDeque - intentionally inefficient!
+    let mut visited = [false; 256];
+    let mut queue = VecDeque::with_capacity(256);
     let mut result = VecDeque::with_capacity(256);
 
     queue.push_back(start);
-    visited.insert(start);
+    visited[start] = true;
 
     while let Some(node) = queue.pop_front() {
         result.push_back(node);
 
         if let Some(neighbors) = graph.adjacency.get(node) {
             for &neighbor in neighbors {
-                if visited.insert(neighbor) {
-                    queue.push_back(neighbor);
-                }
+                visited[neighbor] = true;
+                queue.push_back(neighbor);
             }
         }
     }