public long largestRectangle(int[] h)
{
// first of all i define variable which type is stack.
var _stack = new StackWithLinkedList <int>();
var _maximum_area = 0; //as a result that should return at the end of method
var _lengthOfArray = h.Length;
var _counter = 0;
// secondly start from first bar, and do following for every bar ‘h[i]’ where ‘_counter’ varies from 0 to _lengthOfArray-1.
while (_counter < _lengthOfArray)
{
if (_stack.IsNull() || h[_stack.Peek()] <= h[_counter])
{
_stack.Push(_counter++);
}
else if (h[_stack.Peek()] > h[_counter])
{
//keep top of stack and remove it
var _topOfStack = _stack.Pop();
//calculate with top of stack
var _calculateArea = h[_topOfStack] * (_stack.IsNull() ? _counter : _counter - _stack.Peek() - 1);
if (_maximum_area < _calculateArea)
{
_maximum_area = _calculateArea;
}
}
}
//finally if stack not is null should remove one by one from stack and calculate area with each one
while (!_stack.IsNull())
{
//keep top of stack and remove it
var _topOfStack = _stack.Pop();
//calculate with top of stack
var _calculateArea = h[_topOfStack] * (_stack.IsNull() ? _counter : _counter - _stack.Peek() - 1);
if (_maximum_area < _calculateArea)
{
_maximum_area = _calculateArea;
}
}
return(_maximum_area);
}