private void dfs(DiGraph G, int v)
{
marked[v] = true;
onStack[v] = true;
foreach (var w in G.adj(v))
{
if (!marked[w])
{
edgeTo[w] = v;
dfs(G, w);
}
else if (onStack[w])
{
if (circle == null)
{
return;
}
else
{
circle = new StackLinkedList <int>();
for (var x = w; x != v; x = edgeTo[x])
{
circle.Push(x);
}
circle.Push(v);
circle.Push(w);
}
}
}
onStack[v] = false;
}
public IEnumerable <int> Path(int v)
{
var path = new StackLinkedList <int>();
for (var x = v; x != s; x = edgeTo[x])
{
path.Push(x);
}
path.Push(s);
return(path);
}
public void TestStack()
{
var stack = new StackLinkedList <int>();
stack.Push(10);
stack.Push(20);
Assert.Equal(2, stack.Count);
Assert.False(stack.IsEmpty);
Assert.Equal(20, stack.Pop());
Assert.Equal(10, stack.Pop());
Assert.True(stack.IsEmpty);
}
public void Implement_Stack_Using_LinkedList()
{
var head = new StackNodeSingly <int>(1);
StackLinkedList <int> stack = new StackLinkedList <int>(head);
stack.Push(new StackNodeSingly <int>(2));
stack.Push(new StackNodeSingly <int>(3));
Assert.Equal(3, stack.Pop());
stack.Push(new StackNodeSingly <int>(4));
Assert.Equal(4, stack.Pop());
output.WriteLine(stack.Draw());
}
public static void Main(string[] args)
{
StackLinkedList <string> stackLinkedList = new StackLinkedList <string>();
Console.WriteLine($"Size: {stackLinkedList.Size()}");
Console.WriteLine($"IsEmpty: {stackLinkedList.IsEmpty()}");
Console.WriteLine();
stackLinkedList.Push("John");
stackLinkedList.Push("Sarah");
stackLinkedList.Push("Mario");
Console.WriteLine();
Console.WriteLine($"Size: {stackLinkedList.Size()}");
Console.WriteLine($"IsEmpty: {stackLinkedList.IsEmpty()}");
Console.WriteLine();
Console.WriteLine($"Pop: {stackLinkedList.Pop().ToString()}");
Console.WriteLine($"Peek: {stackLinkedList.Peek().ToString()}");
Console.WriteLine($"Pop: {stackLinkedList.Pop().ToString()}");
Console.WriteLine($"Peek: {stackLinkedList.Peek().ToString()}");
Console.WriteLine();
Console.WriteLine($"Size: {stackLinkedList.Size()}");
// Expected Output
// ------------------
// Size: 0
// IsEmpty: True
//
// Push: John
// Push: Sarah
// Push: Mario
//
// Size: 3
// IsEmpty: False
//
// Pop: Mario
// Peek: Sarah
// Pop: Sarah
// Peek: John
//
// Size: 1
}
public IEnumerable <Edge <T> > PathTo(T v)
{
if (!vertexes.Contains(v))
{
throw new IndexOutOfRangeException("Graph does not contain parameter vertex");
}
if (HasNegativeCycle())
{
throw new Exception("Negative cost cycle exists");
}
if (!HasPathTo(v))
{
return(null);
}
var path = new StackLinkedList <Edge <T> >();
//for (var x = v; x.CompareTo(s) != 0; x = edgeTo[x].Other(x))
//{
// path.Push(edgeTo[x]);
//}
for (var e = edgeTo[v]; e != null; e = edgeTo[e.From()])
{
path.Push(e);
}
return(path);
}
public void PushPop()
{
var stack = new StackLinkedList <int>();
stack.Push(1);
stack.Push(2);
stack.Push(3);
Assert.AreEqual("321", stack.GetValues());
stack.Pop();
Assert.AreEqual("21", stack.GetValues());
stack.Pop();
Assert.AreEqual("1", stack.GetValues());
}
/// <summary>
/// Depth-first search (DFS) is an algorithm for traversing or searching tree or graph data structures.
/// Finds all vertices that can be reached by the starting vertex.
/// </summary>
/// <param name="rootVertex"></param>
/// <param name="previsit"></param>
/// <returns></returns>
public HashSet <T> DepthFirstSearch(T rootVertex, Action <T> preVisit = null)
{
// Traversed graph information
var visitedVerticesInfo = new HashSet <T>();
if (!_aList.ContainsKey(rootVertex))
{
return(visitedVerticesInfo);
}
// Create a stack and add root vertex
var stack = new StackLinkedList <T>();
stack.Push(rootVertex);
// As long as the stack is not empty:
while (!stack.IsEmpty())
{
// Repeatedly pop a vertex u from the queue.
var vertex = stack.Pop();
// Ignore if neigbor is already visited
if (visitedVerticesInfo.Contains(vertex))
{
continue;
}
// Trace the path
preVisit?.Invoke(vertex);
// Add vertex info to the visited list
visitedVerticesInfo.Add(vertex);
// For each neighbor v of u that has not been visited:
foreach (var neighbor in _aList[vertex])
{
if (!visitedVerticesInfo.Contains(neighbor))
{
// Push v
stack.Push(neighbor);
}
}
}
return(visitedVerticesInfo);
}
public void PushElements()
{
var stack = new StackLinkedList <int>();
for (int i = 0; i < MAX_SIZE; i++)
{
stack.Push(i);
}
}
public void StackSizeIncreases()
{
var stack = new StackLinkedList <int>();
for (int i = 0; i < MAX_SIZE; i++)
{
stack.Push(i);
}
Assert.AreEqual(MAX_SIZE, stack.Size());
}
public IEnumerable <Edge> PathTo(int v)
{
var path = new StackLinkedList <Edge>();
for (var x = v; x != s; x = edgeTo[x].from())
{
path.Push(edgeTo[x]);
}
return(path);
}
public void Null_Stack_Using_LinkedList()
{
var head = new StackNodeSingly <int>(1);
StackLinkedList <int> stack = new StackLinkedList <int>(head);
Assert.Equal(1, stack.Pop());
Assert.Equal(0, stack.Pop());
stack.Push(new StackNodeSingly <int>(2));
output.WriteLine(stack.Draw());
}
private void dfs(DiGraph G, int v)
{
marked[v] = true;
foreach (var w in G.adj(v))
{
if (marked[w])
{
continue;
}
dfs(G, w);
}
reversePostOrder.Push(v);
}
public void PopReturnsValue()
{
var stack = new StackLinkedList <int>();
for (int i = 0; i < MAX_SIZE; i++)
{
stack.Push(i);
}
for (int i = MAX_SIZE - 1; i > 0; i--)
{
Assert.AreEqual(i, stack.Pop());
}
}
public void StackSizeDecreases()
{
var stack = new StackLinkedList <int>();
for (int i = 0; i < MAX_SIZE; i++)
{
stack.Push(i);
}
for (int i = MAX_SIZE; i > 0; i--)
{
stack.Pop();
}
Assert.AreEqual(0, stack.Size());
}
public void PushPop()
{
try
{
var stack = new StackLinkedList <int>();
for (int i = 0; i < MAX_SIZE; i++)
{
stack.Push(i);
}
for (int i = MAX_SIZE - 1; i > 0; i--)
{
stack.Pop();
}
}
catch (InvalidOperationException)
{
Assert.Fail("Failed to pop all elements.");
}
}
public void Check_Balanced_Brackets(char[] brackers, bool isBalanced)
{
StackLinkedList <char> stack = new StackLinkedList <char>();
var result = true;
foreach (var item in brackers)
{
switch (item)
{
case '{':
case '[':
case '(':
stack.Push(new StackNodeSingly <char>(item));
break;
case '}':
case ']':
case ')':
char bracket = stack.Pop();
bool isPair = isPairMatch(bracket, item);
if (!isPair)
{
result = false;
}
break;
default:
break;
}
if (!result)
{
break;
}
}
Assert.Equal(isBalanced, result);
}
public void StackIsEmpty()
{
var stack = new StackLinkedList <int>();
InvalidOperationException ex = new InvalidOperationException();
try
{
for (int i = 0; i < MAX_SIZE; i++)
{
stack.Push(i);
}
for (int i = 0; i < MAX_SIZE + 1; i++)
{
stack.Pop();
}
}
catch (InvalidOperationException e)
{
ex = e;
}
Assert.AreEqual("The Stack is empty.", ex.Message);
}