/// <summary>
/// Remove and return the first value in the stack (LIFO).
/// If the stack is empty, default value is returned.
/// Time: O(1).
/// </summary>
/// <returns>The first value in the stack, or default if it's empty</returns>
public ValueType Pop()
{
if (null == StackRoot)
{
return(default(ValueType));
}
ValueType value = StackRoot.Value;
StackRoot = StackRoot.Next;
StackMaxRoot = StackMaxRoot.Next;
return(value);
}
/// <summary>
/// Insert the value on top of the stack.
/// Time: O(1).
/// </summary>
/// <param name="value"></param>
public void Push(ValueType value)
{
LinkedNode <ValueType> valueNode = new LinkedNode <ValueType>(value);
if (null == StackRoot)
{
StackRoot = valueNode;
StackMaxRoot = new LinkedNode <ValueType>(value);
}
else
{
// push nello stack
valueNode.Next = StackRoot;
StackRoot = valueNode;
// aggiornamento max
ValueType max = (value.CompareTo(StackMaxRoot.Value) >= 0) ? value : StackMaxRoot.Value;
LinkedNode <ValueType> maxNode = new LinkedNode <ValueType>(max);
maxNode.Next = StackMaxRoot;
StackMaxRoot = maxNode;
}
}
public LinkedNode(ValueType value)
{
Value = value;
Next = null;
}
public MaxStack()
{
StackRoot = null;
StackMaxRoot = null;
}