/// <summary>
/// A depth first search traversal of the graph, starting from a specified vertex.
/// Returns the visited vertices of the graph.
/// </summary>
public virtual IEnumerable <T> DepthFirstWalk(T source)
{
// Check for existence of source
if (VerticesCount == 0)
{
return(new ArrayListGeneric <T>(0));
}
else if (!HasVertex(source))
{
throw new KeyNotFoundException("The source vertex doesn't exist.");
}
var visited = new HashSet <T>();
var stack = new StackGeneric <T>();
var listOfNodes = new ArrayListGeneric <T>(VerticesCount);
stack.Push(source);
while (!stack.IsEmpty)
{
var current = stack.Pop();
if (!visited.Contains(current))
{
listOfNodes.Add(current);
visited.Add(current);
foreach (var adjacent in Neighbours(current))
{
if (!visited.Contains(adjacent))
{
stack.Push(adjacent);
}
}
}
}
return(listOfNodes);
}
public void StackTests()
{
bool hasException = false;
object peekObject = new object();
object poppedItem = new object();
StackGeneric <int?> stack1 = new StackGeneric <int?>();
StackComparable <int> stack2 = new StackComparable <int>();
StackComparable <string> stack3 = new StackComparable <string>();
#region StackTest :: empty stack<non-nullable>
try
{
peekObject = stack2.Peek();
}
catch (StackOperationException e)
{
hasException = true;
Assert.IsNotNull(e.Message);
}
finally
{
Assert.IsNotNull(peekObject);
Assert.IsTrue(hasException);
}
hasException = false;
try
{
poppedItem = stack2.Pop();
}
catch (StackOperationException e)
{
hasException = true;
Assert.IsNotNull(e.Message);
}
finally
{
Assert.IsNotNull(poppedItem);
Assert.IsTrue(hasException);
}
#endregion
#region StackTest :: empty stack<nullable>
hasException = false;
try
{
peekObject = stack1.Peek();
}
catch (StackOperationException e)
{
hasException = true;
Assert.IsNotNull(e.Message); //should never come here
}
finally
{
Assert.IsFalse(hasException);
Assert.IsNull(peekObject);
}
hasException = false;
try
{
var test1 = "stack3.test1";
stack3.Push(test1);
peekObject = stack3.Peek();
poppedItem = stack3.Pop();
Assert.IsTrue(poppedItem.Equals(peekObject));
Assert.IsTrue(poppedItem.Equals(test1));
Assert.IsNotNull(poppedItem);
poppedItem = stack3.Pop();
}
catch (StackOperationException e)
{
hasException = true;
Assert.IsNotNull(e.Message); //should never come here
}
finally
{
Assert.IsFalse(hasException);
Assert.IsNull(poppedItem);
}
hasException = false;
try
{
peekObject = stack3.Peek();
}
catch (StackOperationException e)
{
hasException = true;
Assert.IsNotNull(e.Message); //should never come here
}
finally
{
Assert.IsFalse(hasException);
Assert.IsNull(peekObject);
}
#endregion
#region StackTest :: Get the minimum in the stack
var test3_1 = "abcd";
var test3_2 = "ABCD";
var test3_3 = "";
var test3_4 = "xyz...12345";
var test3_5 = "5555";
stack3.Push(test3_1);
Assert.IsTrue(test3_1.Equals(stack3.GetMinimum()));
Assert.IsTrue(test3_1.Equals(stack3.Minimum));
stack3.Push(test3_2);
Assert.IsTrue(test3_1.Equals(stack3.GetMinimum()));
Assert.IsTrue(test3_1.Equals(stack3.Minimum));
stack3.Push(test3_3);
Assert.IsTrue(test3_3.Equals(stack3.GetMinimum()));
Assert.IsTrue(test3_3.Equals(stack3.Minimum));
stack3.Pop();
stack3.Push(test3_4);
Assert.IsTrue(test3_1.Equals(stack3.GetMinimum()));
Assert.IsTrue(test3_1.Equals(stack3.Minimum));
stack3.Push(test3_5);
Assert.IsTrue(test3_5.Equals(stack3.GetMinimum()));
Assert.IsTrue(test3_5.Equals(stack3.Minimum));
#endregion
#region StackTest ::
#endregion
}
