public void PUSH(int data)
{
dataStack.PUSH(data);
if (minimumStack.IsEmpty())
{
minimumStack.PUSH(data);
}
else
{
minimumStack.PUSH(data < minimumStack.PEEK() ? data : minimumStack.PEEK());
}
}
/// <summary>
/// Complexity of this code is O(N)
/// </summary>
/// <param name="expression"></param>
/// <returns></returns>
public static bool HasMatchingParans(string expression)
{
try
{
Stack.Stack <char> openPanransFound = new Stack.Stack <char>();
foreach (char expressionChar in expression)
{
if (openParans.Contains(expressionChar))
{
openPanransFound.PUSH(expressionChar);
}
if (matchingOpens.ContainsKey(expressionChar))
{
if (openPanransFound.GetSize() == 0)
{
return(false);
}
if (!matchingOpens.TryGetValue(expressionChar, out char openForTheCloseFound) ||
!openPanransFound.POP().Equals(openForTheCloseFound))
{
return(false);
}
}
}
return(openPanransFound.IsEmpty());
}
catch (Stack.StackOverflowException ex)
{
Console.WriteLine(ex);
}
catch (Stack.StackUnderflowException ex)
{
Console.WriteLine(ex);
}
return(false);
}
public PostFix ToPostFix()
{
List <char> operatorsList = new List <char>()
{
'+', '-', '*', '/'
};
List <char> additiveOp = new List <char>()
{
'+', '-'
};
List <char> multiplicativeOp = new List <char>()
{
'*', '/'
};
string returnString = "";
foreach (char input in Expression) //7
{
if (input > 96 && input < 123) //2
{
_queue.EnQueue(input);
continue;
}
if (input == '(') //3
{
_stack.Push(input);
continue;
}
if (input == ')') //4
{
while ((char)_stack.Peek() != '(')
{
_queue.EnQueue(_stack.Pop());
}
_stack.Pop();
continue;
}
if (operatorsList.Contains(input) && (_stack.GetSize() == 0 || (char)_stack.Peek() == '(')) //5
{
_stack.Push(input);
continue;
}
while (!_stack.IsEmpty() && (additiveOp.Contains(input) && multiplicativeOp.Contains((char)_stack.Peek()))) //6
{
if (operatorsList.Contains(input) && !_stack.IsEmpty())
{
if (additiveOp.Contains(input) && multiplicativeOp.Contains((char)_stack.Peek()))
{
_queue.EnQueue(_stack.Pop());
}
else
{
_stack.Push(input);
}
}
}
}
while (!_stack.IsEmpty())
{
_queue.EnQueue(_stack.Pop());
}
while (!_queue.IsEmpty())
{
returnString += _queue.DeQueue();
}
return(new PostFix(returnString));
}
