public void UpdatingAndGettingEdgeWeight()
{
var vertices = new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
var graph = new DirectedWeightedALGraph <int, int>();
graph.AddVertices(vertices);
Assert.IsTrue(graph.VerticesCount == vertices.Length);
foreach (var vertex in vertices)
{
Assert.IsTrue(graph.ContainsVertex(vertex));
}
// Graph is:
// 1 -> 3, 4
// 1 <- 2
// 2 -> 1, 5
// 2 <- 3, 5, 6
// 3 -> 2, 6
// 3 <- 1, 4
// 4 -> 3, 6
// 4 <- 1, 7
// 5 -> 2, 7, 8
// 5 <- 2, 8
// 6 -> 2
// 6 <- 3, 4
// 7 -> 4
// 7 <- 5, 8
// 8 -> 5, 7
// 8 <- 5
// 9 ->
// 9 <-
// With each edge having a weight of the diffrenece between the source and destination vertex (source - destination)
graph.AddEdge(1, 3, -2);
graph.AddEdge(1, 4, -3);
graph.AddEdge(2, 1, 1);
graph.AddEdge(2, 5, -3);
graph.AddEdge(3, 2, 1);
graph.AddEdge(3, 6, -3);
graph.AddEdge(4, 3, 1);
graph.AddEdge(4, 6, -2);
graph.AddEdge(5, 2, 3);
graph.AddEdge(5, 7, -2);
graph.AddEdge(5, 8, -3);
graph.AddEdge(6, 2, 4);
graph.AddEdge(7, 4, 3);
graph.AddEdge(8, 5, 3);
graph.AddEdge(8, 7, 1);
int weight = 0;
Assert.IsTrue(graph.TryGetEdgeWeight(1, 3, out weight));
Assert.IsTrue(weight == -2);
Assert.IsTrue(graph.UpdateEdgeWeight(1, 3, weight * 2));
Assert.IsTrue(graph.TryGetEdgeWeight(1, 3, out weight));
Assert.IsTrue(weight == -4);
Assert.IsTrue(graph.TryGetEdgeWeight(1, 4, out weight));
Assert.IsTrue(weight == -3);
Assert.IsTrue(graph.UpdateEdgeWeight(1, 4, weight * 2));
Assert.IsTrue(graph.TryGetEdgeWeight(1, 4, out weight));
Assert.IsTrue(weight == -6);
Assert.IsTrue(graph.TryGetEdgeWeight(2, 1, out weight));
Assert.IsTrue(weight == 1);
Assert.IsTrue(graph.UpdateEdgeWeight(2, 1, weight * 2));
Assert.IsTrue(graph.TryGetEdgeWeight(2, 1, out weight));
Assert.IsTrue(weight == 2);
Assert.IsTrue(graph.TryGetEdgeWeight(2, 5, out weight));
Assert.IsTrue(weight == -3);
Assert.IsTrue(graph.UpdateEdgeWeight(2, 5, weight * 2));
Assert.IsTrue(graph.TryGetEdgeWeight(2, 5, out weight));
Assert.IsTrue(weight == -6);
Assert.IsTrue(graph.TryGetEdgeWeight(3, 2, out weight));
Assert.IsTrue(weight == 1);
Assert.IsTrue(graph.UpdateEdgeWeight(3, 2, weight * 2));
Assert.IsTrue(graph.TryGetEdgeWeight(3, 2, out weight));
Assert.IsTrue(weight == 2);
Assert.IsTrue(graph.TryGetEdgeWeight(3, 6, out weight));
Assert.IsTrue(weight == -3);
Assert.IsTrue(graph.UpdateEdgeWeight(3, 6, weight * 2));
Assert.IsTrue(graph.TryGetEdgeWeight(3, 6, out weight));
Assert.IsTrue(weight == -6);
Assert.IsTrue(graph.TryGetEdgeWeight(4, 3, out weight));
Assert.IsTrue(weight == 1);
Assert.IsTrue(graph.UpdateEdgeWeight(4, 3, weight * 2));
Assert.IsTrue(graph.TryGetEdgeWeight(4, 3, out weight));
Assert.IsTrue(weight == 2);
Assert.IsTrue(graph.TryGetEdgeWeight(4, 6, out weight));
Assert.IsTrue(weight == -2);
Assert.IsTrue(graph.UpdateEdgeWeight(4, 6, weight * 2));
Assert.IsTrue(graph.TryGetEdgeWeight(4, 6, out weight));
Assert.IsTrue(weight == -4);
Assert.IsTrue(graph.TryGetEdgeWeight(5, 2, out weight));
Assert.IsTrue(weight == 3);
Assert.IsTrue(graph.UpdateEdgeWeight(5, 2, weight * 2));
Assert.IsTrue(graph.TryGetEdgeWeight(5, 2, out weight));
Assert.IsTrue(weight == 6);
Assert.IsTrue(graph.TryGetEdgeWeight(5, 7, out weight));
Assert.IsTrue(weight == -2);
Assert.IsTrue(graph.UpdateEdgeWeight(5, 7, weight * 2));
Assert.IsTrue(graph.TryGetEdgeWeight(5, 7, out weight));
Assert.IsTrue(weight == -4);
Assert.IsTrue(graph.TryGetEdgeWeight(5, 8, out weight));
Assert.IsTrue(weight == -3);
Assert.IsTrue(graph.UpdateEdgeWeight(5, 8, weight * 2));
Assert.IsTrue(graph.TryGetEdgeWeight(5, 8, out weight));
Assert.IsTrue(weight == -6);
Assert.IsTrue(graph.TryGetEdgeWeight(6, 2, out weight));
Assert.IsTrue(weight == 4);
Assert.IsTrue(graph.UpdateEdgeWeight(6, 2, weight * 2));
Assert.IsTrue(graph.TryGetEdgeWeight(6, 2, out weight));
Assert.IsTrue(weight == 8);
Assert.IsTrue(graph.TryGetEdgeWeight(7, 4, out weight));
Assert.IsTrue(weight == 3);
Assert.IsTrue(graph.UpdateEdgeWeight(7, 4, weight * 2));
Assert.IsTrue(graph.TryGetEdgeWeight(7, 4, out weight));
Assert.IsTrue(weight == 6);
Assert.IsTrue(graph.TryGetEdgeWeight(8, 5, out weight));
Assert.IsTrue(weight == 3);
Assert.IsTrue(graph.UpdateEdgeWeight(8, 5, weight * 2));
Assert.IsTrue(graph.TryGetEdgeWeight(8, 5, out weight));
Assert.IsTrue(weight == 6);
Assert.IsTrue(graph.TryGetEdgeWeight(8, 7, out weight));
Assert.IsTrue(weight == 1);
Assert.IsTrue(graph.UpdateEdgeWeight(8, 7, weight * 2));
Assert.IsTrue(graph.TryGetEdgeWeight(8, 7, out weight));
Assert.IsTrue(weight == 2);
}