Exemple #1
0
        public void TopologicalSort_ValidGraph_SortsCorrectly()
        {
            // arrange
            GraphNode openDoor = new GraphNode("open door");
            GraphNode unlockCar = new GraphNode("unlock car");
            GraphNode getInCar = new GraphNode("get in car");
            GraphNode turnOnEngine = new GraphNode("turn on engine");
            GraphNode adjustMirrors = new GraphNode("adjust mirrors");
            GraphNode turnOnHeadlights = new GraphNode("turn on headlights");

            unlockCar.Paths.Add(openDoor);
            openDoor.Paths.Add(getInCar);
            getInCar.Paths.Add(adjustMirrors);
            getInCar.Paths.Add(turnOnHeadlights);
            adjustMirrors.Paths.Add(turnOnEngine);
            turnOnHeadlights.Paths.Add(turnOnEngine);

            GraphNode[] nodes = new GraphNode[] { adjustMirrors, turnOnHeadlights, openDoor, unlockCar, getInCar, turnOnEngine, };
            GraphNavigator navigator = new GraphNavigator();

            // act
            GraphNode[] topologicalSort = navigator.TopologicalSort(nodes).ToArray();

            // assert
            Assert.AreEqual(topologicalSort[0], unlockCar);
            Assert.AreEqual(topologicalSort[1], openDoor);
            Assert.AreEqual(topologicalSort[2], getInCar);
            Assert.IsTrue(topologicalSort[3] == adjustMirrors || topologicalSort[3] == turnOnHeadlights);
            Assert.IsTrue(topologicalSort[4] == adjustMirrors || topologicalSort[4] == turnOnHeadlights);
            Assert.AreEqual(topologicalSort[5], turnOnEngine);
            Assert.AreEqual(topologicalSort.Length, 6);
        }
Exemple #2
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        public IEnumerable<GraphNode> TopologicalSort(GraphNode[] graph)
        {
            HashSet<GraphNode> visited = new HashSet<GraphNode>();
            Stack<GraphNode> sorted = new Stack<GraphNode>();
            foreach (GraphNode node in graph)
            {
                TopologicalSort(node, visited, sorted);
            }

            return sorted;
        }
Exemple #3
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        private void TopologicalSort(GraphNode node, HashSet<GraphNode> visited, Stack<GraphNode> sorted)
        {
            if (visited.Contains(node)) return;

            visited.Add(node);
            foreach (GraphNode n in node.Paths)
            {
                TopologicalSort(n, visited, sorted);
            }

            sorted.Push(node);
        }