From c488cfa1a9f0727f41ed19a4de33503d0093efcb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Kn=C3=BCttel?= <daniel.knuettel@daknuett.eu>
Date: Sat, 2 Feb 2019 16:45:15 +0100
Subject: [PATCH] add module that provides answers to the questions

---
 exam/ex01/connectivity.py | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)
 create mode 100644 exam/ex01/connectivity.py

diff --git a/exam/ex01/connectivity.py b/exam/ex01/connectivity.py
new file mode 100644
index 0000000..c7af3fe
--- /dev/null
+++ b/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))
+