BittStone problem

<?php

declare(strict_types=1);

class IOHandler
{
    /**
     * @var resource
     */
	private $inputDescriptor;

    /**
     * @var resource
     */
    private $outputDescriptor;

    /**
     * IOHandler constructor.
     *
     * @param string $in
     * @param string $out
     */
	public function __construct(string $in = 'php://stdin', string $out = 'php://stdout')
	{
		$this->inputDescriptor  = fopen($in, 'r');
		$this->outputDescriptor = fopen($out, 'w');
	}

    /**
     * @param string $prompt
     *
     * @return int
     */
	public function readInt(string $prompt = '') : int
	{
		$this->write($prompt);
		fscanf($this->inputDescriptor, "%d", $ret);

        return $ret;
	}

    /**
     * @param $message
     *
     * @return IOHandler
     */
	public function write($message) : IOHandler
	{
		fwrite($this->outputDescriptor, (string) $message);
	
		return $this;
	}

    /**
     * @param $message
     *
     * @return IOHandler
     */
	public function writeln($message) : IOHandler
	{	
		$this->write($message);
		$this->write(PHP_EOL);
		
		return $this;
	}
}

class ElementGetter
{
    /**
     * @var int
     */
    private $n;

    /**
     * ElementGetter constructor.
     *
     * @param int $n
     */
    public function __construct(int $n)
    {
        $this->n = $n;
    }

    /**
     * @param int $line
     * @param int $column
     * @return int
     */
    public function getElementAt(int $line, int $column) : int
    {
        if ($this->isAboveAndSecondaryDiagonal($line, $column)) {
            return $this->getAboveAndSecondaryDiagonal($line, $column);
        } elseif ($this->isBelowSecondaryDiagonal($line, $column)) {
            return $this->getBelowSecondaryDiagonal($line, $column);
        } else {
            return $this->getBelowSecondaryDiagonalWithOneIndex($line, $column);
        }
    }

    /**
     * @param int $line
     * @param int $column
     * @return bool
     */
    private function isAboveAndSecondaryDiagonal(int $line, int $column) : bool
    {
        return $line + $column <= $this->n + 1;
    }

    /**
     * @param int $line
     * @param int $column
     * @return bool
     */
    private function isBelowSecondaryDiagonal(int $line, int $column) : bool
    {
        return $line + $column > $this->n + 2;
    }

    /**
     * @param int $line
     * @param int $column
     * @return int
     */
    private function getAboveAndSecondaryDiagonal(int $line, int $column) : int
    {
        return (($line + $column - 2) * ($line + $column - 1)) / 2 + $column;
    }

    /**
     * @param int $line
     * @param int $column
     * @return int
     */
    private function getBelowSecondaryDiagonalWithOneIndex(int$line, int $column) : int{
        return $this->getAboveAndSecondaryDiagonal($line-1, $column) + ($this->n - 1);
    }

    /**
     * @param int $line
     * @param int $column
     * @return int
     */
    private function getBelowSecondaryDiagonal(int $line, int $column) : int
    {
        return $this->getBelowSecondaryDiagonalWithOneIndex( $this->n - $column + 2, $column) +
            ((($this->n - 2) * ($this->n - 1)) - ((2 * $this->n - $line - $column)* (2 * $this->n - $line - $column + 1))) / 2;
    }
}

$handler = new IOHandler();

$n      = $handler->readInt("n      = ");
$line   = $handler->readInt("line   = ");
$column = $handler->readInt("column = ");

$getter = new ElementGetter($n);

$handler
    ->write("The element at line ")
    ->write($line)
    ->write(" and column ")
    ->write($column)
    ->write(" is: ")
    ->writeln($getter->getElementAt($line, $column))
;

Very nice, you did i good job. This is fucking great man, how not to love it? GG man GG

Mihai, your sarcasm always amazes me :))