function getLightState(array $grid, $r, $c)
{
if (($r === 0 || $r === count($grid) - 1) && ($c === 0 || $c === count($grid[$r]) - 1)) {
return 1;
}
$neighbors = countNeighbors($grid, $r, $c);
if ($grid[$r][$c] === 1) {
return $neighbors === 2 || $neighbors === 3 ? 1 : 0;
}
return $neighbors === 3 ? 1 : 0;
}
$n += get($grid, $r - 1, $c - 1);
$n += get($grid, $r - 1, $c);
$n += get($grid, $r - 1, $c + 1);
$n += get($grid, $r, $c - 1);
$n += get($grid, $r, $c + 1);
$n += get($grid, $r + 1, $c - 1);
$n += get($grid, $r + 1, $c);
$n += get($grid, $r + 1, $c + 1);
return $n;
}
function get(array $grid, $r, $c)
{
return isset($grid[$r][$c]) ? $grid[$r][$c] : 0;
}
$num = 0;
for ($i = 0; $i < $steps; $i++) {
$newGrid = array();
$num = 0;
foreach ($grid as $r => $row) {
foreach ($row as $c => $cell) {
$neighbors = countNeighbors($grid, $r, $c);
if ($cell === 1) {
$num += $newGrid[$r][$c] = $neighbors === 2 || $neighbors === 3 ? 1 : 0;
} else {
$num += $newGrid[$r][$c] = $neighbors === 3 ? 1 : 0;
}
}
}
$grid = $newGrid;
}
echo 'Answer: ' . $num . PHP_EOL;