/// <summary>
/// Computes total wieghts from start node for all nodes in graph
/// </summary>
public Dijkstra Compute(DijkstraGraph graph)
{
while (graph.HasUnvisited())
{
var current = graph.NearestUnvisited();
foreach (var node in graph.Linked(current))
{
var weightFromCurrent = current.TotalWeigth + current.LinkWeight(node);
// if this way shorter
if (!node.TotalWeigth.HasValue || weightFromCurrent < node.TotalWeigth)
{
node.TotalWeigth = weightFromCurrent;
node.Previous = current;
}
}
current.IsVisited = true;
}
return this;
}
public void NearestUnvisited_ReturnsFirstUnvisitedWithMinimalMark_Test()
{
// Arrange
var node1 = Mock.Of<DijkstraNode>(t => t.IsVisited == false && t.TotalWeigth == 3);
var node2 = Mock.Of<DijkstraNode>(t => t.IsVisited == false && t.TotalWeigth == 3);
var node3 = Mock.Of<DijkstraNode>(t => t.IsVisited == false && t.TotalWeigth == 10);
var node4 = Mock.Of<DijkstraNode>(t => t.IsVisited == true && t.TotalWeigth == 1);
var graph = new DijkstraGraph()
{
Nodes = new[]
{
node1, node2, node3, node4
}
};
// Act
var nearest = graph.NearestUnvisited();
// Assert
Assert.AreEqual(nearest, node1);
}
public void NearestVisited_ThrowsIfHasNotUnvisited_Test()
{
// Arrange
var graph = new DijkstraGraph()
{
Nodes = new[]
{
Mock.Of<DijkstraNode>(t => t.IsVisited),
Mock.Of<DijkstraNode>(t => t.IsVisited == false && t.TotalWeigth == null)
}
};
// Assert
Assert.Throws<GraphHasNotUnvisitedNodesException>(() => graph.NearestUnvisited());
}
