Merge 7a2ee6eba2 into 6c92c5a539

sorts/topological_sort.py

@@ -15,27 +15,27 @@ edges: dict[str, list[str]] = {
 vertices: list[str] = ["a", "b", "c", "d", "e"]
 
 
-def topological_sort(start: str, visited: list[str], sort: list[str]) -> list[str]:
-    """Perform topological sort on a directed acyclic graph."""
-    current = start
-    # add current to visited
-    visited.append(current)
-    neighbors = edges[current]
-    for neighbor in neighbors:
-        # if neighbor not in visited, visit
-        if neighbor not in visited:
-            sort = topological_sort(neighbor, visited, sort)
-    # if all neighbors visited add current to sort
-    sort.append(current)
-    # if all vertices haven't been visited select a new one to visit
-    if len(visited) != len(vertices):
-        for vertice in vertices:
-            if vertice not in visited:
-                sort = topological_sort(vertice, visited, sort)
-    # return sort
-    return sort
+class Topo:
+    def topo_sort(self):
+        visited = set()
+        stack = []
+
+        def dfs(node):
+            visited.add(node)
+
+            for neighbor in edges[node]:
+                if neighbor not in visited:
+                    dfs(neighbor)
+
+            stack.append(node)
+
+            return stack
+
+        result = dfs("a")
+        return result[::-1]
 
 
 if __name__ == "__main__":
-    sort = topological_sort("a", [], [])
+    topo = Topo()
+    sort = topo.topo_sort()
     print(sort)