add module that provides answers to the questions

exam/ex01/connectivity.py

@@ -0,0 +1,26 @@
+from collections import deque
+
+def can_reach(title, connection):
+	cursor = connection.cursor()
+	cursor.execute("SELECT COUNT(destination) FROM links WHERE destination=?", (title, ))
+	count = cursor.fetchone()[0]
+	return count > 0
+
+def shortest_path(center, title, connection):
+	if(not can_reach(title, connection)):
+		return []
+
+	cursor = connection.cursor()
+	current_title = title
+	path = deque()
+	while(current_title != center):
+		path.append(current_title)
+		cursor.execute('''SELECT links.source 
+				FROM links
+				LEFT JOIN dijkstra_helper ON links.destination=dijkstra_helper.name
+				WHERE links.destination=:title
+				ORDER BY dijkstra_helper.value ASC
+				LIMIT 1''', {"title": current_title})
+		current_title = cursor.fetchone()[0]
+	return list(reversed(path))
+