From cd50f73069ad7c842ee9378229ef95fa13b7fced Mon Sep 17 00:00:00 2001
From: Donne Martin <donne.martin@gmail.com>
Date: Sat, 10 Sep 2016 07:42:21 -0400
Subject: [PATCH] Move graph path exists to a class

---
 .../path_exists_challenge.ipynb               | 16 +++----
 .../path_exists_solution.ipynb                | 42 ++++++++++---------
 .../graph_path_exists/test_path_exists.py     |  8 ++--
 3 files changed, 35 insertions(+), 31 deletions(-)

diff --git a/graphs_trees/graph_path_exists/path_exists_challenge.ipynb b/graphs_trees/graph_path_exists/path_exists_challenge.ipynb
index 51a3100..8ffdb97 100644
--- a/graphs_trees/graph_path_exists/path_exists_challenge.ipynb
+++ b/graphs_trees/graph_path_exists/path_exists_challenge.ipynb
@@ -106,9 +106,11 @@
    },
    "outputs": [],
    "source": [
-    "def path_exists(start, end):\n",
-    "    # TODO: Implement me\n",
-    "    pass"
+    "class GraphPathExists(Graph):\n",
+    "\n",
+    "    def path_exists(self, start, end):\n",
+    "        # TODO: Implement me\n",
+    "        pass"
    ]
   },
   {
@@ -141,7 +143,7 @@
     "\n",
     "    def test_path_exists(self):\n",
     "        nodes = []\n",
-    "        graph = Graph()\n",
+    "        graph = GraphPathExists()\n",
     "        for id in range(0, 6):\n",
     "            nodes.append(graph.add_node(id))\n",
     "        graph.add_edge(0, 1, 5)\n",
@@ -153,9 +155,9 @@
     "        graph.add_edge(3, 2, 7)\n",
     "        graph.add_edge(3, 4, 8)\n",
     "\n",
-    "        assert_equal(path_exists(nodes[0], nodes[2]), True)\n",
-    "        assert_equal(path_exists(nodes[0], nodes[0]), True)\n",
-    "        assert_equal(path_exists(nodes[4], nodes[5]), False)\n",
+    "        assert_equal(graph.path_exists(nodes[0], nodes[2]), True)\n",
+    "        assert_equal(graph.path_exists(nodes[0], nodes[0]), True)\n",
+    "        assert_equal(graph.path_exists(nodes[4], nodes[5]), False)\n",
     "\n",
     "        print('Success: test_path_exists')\n",
     "\n",
diff --git a/graphs_trees/graph_path_exists/path_exists_solution.ipynb b/graphs_trees/graph_path_exists/path_exists_solution.ipynb
index 899ee08..da45b70 100644
--- a/graphs_trees/graph_path_exists/path_exists_solution.ipynb
+++ b/graphs_trees/graph_path_exists/path_exists_solution.ipynb
@@ -124,23 +124,25 @@
     "from collections import deque\n",
     "\n",
     "\n",
-    "def path_exists(start, end):\n",
-    "    if start is None or end is None:\n",
-    "        return False\n",
-    "    if start is end:\n",
-    "        return True\n",
-    "    queue = deque()\n",
-    "    queue.append(start)\n",
-    "    start.visit_state = State.visited\n",
-    "    while queue:\n",
-    "        node = queue.popleft()\n",
-    "        if node is end:\n",
+    "class GraphPathExists(Graph):\n",
+    "\n",
+    "    def path_exists(self, start, end):\n",
+    "        if start is None or end is None:\n",
+    "            return False\n",
+    "        if start is end:\n",
     "            return True\n",
-    "        for adj_node in node.adjacent:\n",
-    "            if adj_node.visit_state == State.unvisited:\n",
-    "                queue.append(adj_node)\n",
-    "                adj_node.visit_state = State.visited\n",
-    "    return False"
+    "        queue = deque()\n",
+    "        queue.append(start)\n",
+    "        start.visit_state = State.visited\n",
+    "        while queue:\n",
+    "            node = queue.popleft()\n",
+    "            if node is end:\n",
+    "                return True\n",
+    "            for adj_node in node.adj_nodes.values():\n",
+    "                if adj_node.visit_state == State.unvisited:\n",
+    "                    queue.append(adj_node)\n",
+    "                    adj_node.visit_state = State.visited\n",
+    "        return False"
    ]
   },
   {
@@ -174,7 +176,7 @@
     "\n",
     "    def test_path_exists(self):\n",
     "        nodes = []\n",
-    "        graph = Graph()\n",
+    "        graph = GraphPathExists()\n",
     "        for id in range(0, 6):\n",
     "            nodes.append(graph.add_node(id))\n",
     "        graph.add_edge(0, 1, 5)\n",
@@ -186,9 +188,9 @@
     "        graph.add_edge(3, 2, 7)\n",
     "        graph.add_edge(3, 4, 8)\n",
     "\n",
-    "        assert_equal(path_exists(nodes[0], nodes[2]), True)\n",
-    "        assert_equal(path_exists(nodes[0], nodes[0]), True)\n",
-    "        assert_equal(path_exists(nodes[4], nodes[5]), False)\n",
+    "        assert_equal(graph.path_exists(nodes[0], nodes[2]), True)\n",
+    "        assert_equal(graph.path_exists(nodes[0], nodes[0]), True)\n",
+    "        assert_equal(graph.path_exists(nodes[4], nodes[5]), False)\n",
     "\n",
     "        print('Success: test_path_exists')\n",
     "\n",
diff --git a/graphs_trees/graph_path_exists/test_path_exists.py b/graphs_trees/graph_path_exists/test_path_exists.py
index a99bca0..a7374c7 100644
--- a/graphs_trees/graph_path_exists/test_path_exists.py
+++ b/graphs_trees/graph_path_exists/test_path_exists.py
@@ -5,7 +5,7 @@ class TestPathExists(object):
 
     def test_path_exists(self):
         nodes = []
-        graph = Graph()
+        graph = GraphPathExists()
         for id in range(0, 6):
             nodes.append(graph.add_node(id))
         graph.add_edge(0, 1, 5)
@@ -17,9 +17,9 @@ class TestPathExists(object):
         graph.add_edge(3, 2, 7)
         graph.add_edge(3, 4, 8)
 
-        assert_equal(path_exists(nodes[0], nodes[2]), True)
-        assert_equal(path_exists(nodes[0], nodes[0]), True)
-        assert_equal(path_exists(nodes[4], nodes[5]), False)
+        assert_equal(graph.path_exists(nodes[0], nodes[2]), True)
+        assert_equal(graph.path_exists(nodes[0], nodes[0]), True)
+        assert_equal(graph.path_exists(nodes[4], nodes[5]), False)
 
         print('Success: test_path_exists')