From 9ba52e80f1f309af9bf99310dce4b107403d81e0 Mon Sep 17 00:00:00 2001
From: Daniel Knuettel <knd35666@gw.ngate.uni-regensburg.de>
Date: Wed, 27 Feb 2019 11:41:44 +0100
Subject: [PATCH] fixed one bug in dijkstra backtracking

---
 exam/ex01/cfg.py   | 2 +-
 exam/ex01/graph.py | 5 +++--
 exam/ex01/main.py  | 8 +++++---
 exam/ex01/sql.py   | 2 +-
 4 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/exam/ex01/cfg.py b/exam/ex01/cfg.py
index 891f03d..15a65db 100644
--- a/exam/ex01/cfg.py
+++ b/exam/ex01/cfg.py
@@ -1,6 +1,6 @@
 
 config = {
-	"use_sqlite": False
+	"use_sqlite": True
 	, "mysql_server": "172.17.0.2"
 	, "mysql_user": "wikipedia"
 	, "mysql_password": "wikipediastuff"
diff --git a/exam/ex01/graph.py b/exam/ex01/graph.py
index 79a8eea..81ff8f7 100644
--- a/exam/ex01/graph.py
+++ b/exam/ex01/graph.py
@@ -27,7 +27,8 @@ class DijkstraHelper(object):
 		return cls(nodes, connections)
 
 	def dijkstra(self, root):
-		self.recursive_dijkstra([root], 0)
+		self._nodes[root] = 0
+		self.recursive_dijkstra([root], 1)
 
 	def recursive_dijkstra(self, todos, depth):
 		if(not todos):
@@ -58,4 +59,4 @@ class DijkstraHelper(object):
 		cursor.executemany(sql.statements["insert_dijkstra_values"], [(k, sqlize(v)) for k,v in self._nodes.items()])
 
 
-			
+		connection.commit()	
diff --git a/exam/ex01/main.py b/exam/ex01/main.py
index 4cacf25..fb6b8ad 100644
--- a/exam/ex01/main.py
+++ b/exam/ex01/main.py
@@ -9,7 +9,7 @@ from dijkstra import prepare_dijkstra, dijkstra
 from connectivity import shortest_path
 
 from graph import DijkstraHelper
-from db_util import get_page_id
+from db_util import get_page_id, get_page_title
 
 cache = get_cache("./cache/", "Angela_Merkel")
 receive_link_graph("Angela_Merkel", cache, 2)
@@ -21,7 +21,6 @@ print(cursor.fetchall())
 #prepare_dijkstra(cache)
 #dijkstra("Angela_Merkel", cache)
 #
-#print(shortest_path("Angela_Merkel", "Germany", cache))
 
 
 angela = get_page_id("Angela_Merkel", cache)
@@ -29,4 +28,7 @@ angela = get_page_id("Angela_Merkel", cache)
 dijkstra = DijkstraHelper.from_db(cache)
 dijkstra.dijkstra(angela)
 dijkstra.write_back(cache)
-print({k:v for k,v in dijkstra._nodes.items() if v != float("inf")})
+#print({k:v for k,v in dijkstra._nodes.items() if v != float("inf")})
+print([get_page_title(id_, cache) for id_ in shortest_path("Angela_Merkel", "Germany", cache)])
+print([get_page_title(id_, cache) for id_ in shortest_path("Angela_Merkel", "2012_Nobel_Peace_Prize", cache)])
+
diff --git a/exam/ex01/sql.py b/exam/ex01/sql.py
index 34b4989..352e103 100644
--- a/exam/ex01/sql.py
+++ b/exam/ex01/sql.py
@@ -29,7 +29,7 @@ sql_statements = {
 			, "mysql": "SELECT COUNT(destination) FROM links WHERE destination=%s"}
 	, "dijkstra_backtrack_one": {"sqlite": '''SELECT links.source 
                                 FROM links
-                                LEFT JOIN dijkstra_helper ON links.destination=dijkstra_helper.page
+                                LEFT JOIN dijkstra_helper ON links.source=dijkstra_helper.page
                                 WHERE links.destination=?
                                 ORDER BY dijkstra_helper.value ASC
                                 LIMIT 1'''