<?php
$input = 3214;

$grid = [];

$x = 1;
while ($x < 301){
  $y = 1;

  $rack_id = $x + 10;

  while ($y < 301) {
    $power_level = $rack_id * $y;
    $power_level += $input;
    $power_level *= $rack_id;
    if ($power_level < 100) {
      $power_level = 0;
    } else {
      $power_level = substr($power_level, -3, 1);
    }
    $power_level -= 5;
    $grid[$x][$y] = $power_level;
    $y++;
  }
  $x++;
}

$strongest_power_level = [
  'cell'  => [
    'x'    => null,
    'y'    => null,
    'size' => null,
  ],
  'level' => null,
];

$square_power_levels = [];

foreach ($grid as $x => $y_row) {
  foreach ($y_row as $y => $power_level) {
    $size = 1;
    $this_power_level = 0;
    while ($size <= (301 - $x) && $size <= (301 - $y)) {
      $x_pointer = $x;
      while ($x_pointer < $x + $size) {
        $this_power_level += $grid[$x_pointer][$y + $size - 1];
        $x_pointer++;
      }
      $y_pointer = $y;
      while ($y_pointer < ($y + $size - 1)) {
        $this_power_level += $grid[$x + $size - 1][$y_pointer];
        $y_pointer++;
      }
      if ($this_power_level > $strongest_power_level['level'] || $strongest_power_level['level'] === null) {
        $strongest_power_level['cell']['x']    = $x;
        $strongest_power_level['cell']['y']    = $y;
        $strongest_power_level['cell']['size'] = $size;
        $strongest_power_level['level']        = $this_power_level;
      }
      $size++;
    }
  }
}

echo $strongest_power_level['cell']['x'] . "," . $strongest_power_level['cell']['y'] . "," . $strongest_power_level['cell']['size'];