Add the topological sort sample and the solution

notes-and-examples/2026.08.27/topological_sort.py

@@ -0,0 +1,21 @@
+from collections import deque
+# double-ended queue, this may be helpful
+# see the docs: https://docs.python.org/3/library/collections.html#collections.deque
+
+classes = {
+    'CPSC 230': {'CPSC 231'},
+    'CPSC 231': {'CPSC 350', 'CPSC 330'},
+    'CPSC 350': {'CPSC 380', 'CPSC 408', 'CPSC 406'},
+    'CPSC 330': {'CPSC 351'},
+    'CPSC 351': set(),
+    'ENGR 101': set(),
+    'CPSC 380': set(),
+    'CPSC 406': set(),
+    'CPSC 408': set()
+}
+
+def topological_sort(adjacency_list: dict[str, set[str]]):
+    # return the sorted ordering
+    return []
+
+print(topological_sort(classes))