public static void PeekAtStackNode()
{
//Arrange
StackAndQueue.Stack stack = new StackAndQueue.Stack(new Node(1));
stack.Push(new Node(5));
stack.Push(new Node(6));
stack.Push(new Node(7));
stack.Push(new Node(8));
stack.Push(new Node(9));
//Act
stack.Peek();
//Assert
Assert.Equal(9, stack.Top.Value);
}
public static void Parentheses()
{
Console.WriteLine("Please enter string with brackets:");
string k = Console.ReadLine();
Stack stack = new Stack(k.Length);
int a = 0, b = 0;
//Traverse string.
for (int i = 0; i < k.Length; i++)
{
string str = k[i].ToString();
//push left parenthesis to stack.
if (str.Equals("(") || str.Equals("{") || str.Equals("["))
{
stack.Push(k[i]);
a++;
}
//pop left parenthesis which is correspond right parenthesis
while (str.Equals(")"))
{
b++;
if (!stack.IsEmpty() && stack.Peek().ToString().Equals("("))
{
stack.Pop();
break;
}
else
{
Console.WriteLine("invalid Parentheses");
return;
}
}
while (str.Equals("]"))
{
b++;
if (!stack.IsEmpty() && stack.Peek().ToString().Equals("["))
{
stack.Pop();
break;
}
else
{
Console.WriteLine("invalid Parentheses");
return;
}
}
while (str.Equals("}"))
{
b++;
if (!stack.IsEmpty() && stack.Peek().ToString().Equals("{"))
{
stack.Pop();
break;
}
else
{
Console.WriteLine("invalid Parentheses");
return;
}
}
}
if (stack.IsEmpty() && a - b == 0)
{
Console.WriteLine("Valid Parentheses");
}
else if (a > b)
{
Console.WriteLine("invalid Parentheses");
}
}
