102 lines
2.6 KiB
PHP
102 lines
2.6 KiB
PHP
|
<?php
|
||
|
|
|
||
|
|
$seats = explode("\n", file_get_contents('input.txt'));
|
||
|
|
|
||
|
|
array_walk($seats, static function(&$seat) {
|
||
|
|
$seat = str_split($seat);
|
||
|
|
});
|
||
|
|
|
||
|
|
function checkAdjacentSeats($seats, $row, $col)
|
||
|
|
{
|
||
|
|
$adjacent_seats = [
|
||
|
|
'L' => 0,
|
||
|
|
'.' => 0,
|
||
|
|
'#' => 0,
|
||
|
|
];
|
||
|
|
for ($i = $row - 1; $i <= $row + 1; $i++) {
|
||
|
|
if (array_key_exists($i, $seats)) {
|
||
|
|
for ($j = $col - 1; $j <= $col + 1; $j++) {
|
||
|
|
if ($i === $row && $j === $col) {
|
||
|
|
continue; // ignore current seat !
|
||
|
|
}
|
||
|
|
if (array_key_exists($j, $seats[$i])) {
|
||
|
|
$adjacent_seats[$seats[$i][$j]]++;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return $adjacent_seats;
|
||
|
|
}
|
||
|
|
|
||
|
|
function makeARound($seats)
|
||
|
|
{
|
||
|
|
$new_seats = $seats;
|
||
|
|
for ($row = 0, $row_count = count($seats); $row < $row_count; $row++) {
|
||
|
|
for ($col = 0, $col_count = count($seats[0]); $col < $col_count; $col++) {
|
||
|
|
$current = $seats[$row][$col];
|
||
|
|
if ('.' === $current) {
|
||
|
|
continue;
|
||
|
|
}
|
||
|
|
|
||
|
|
$adjacent_seats = checkAdjacentSeats($seats, $row, $col);
|
||
|
|
if ('L' === $current) {
|
||
|
|
// check adjacent seat, if all empty => it becomes # else nothing
|
||
|
|
if ($adjacent_seats['#'] === 0) {
|
||
|
|
$new_seats[$row][$col] = '#';
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
if ('#' === $current) {
|
||
|
|
// check adjacent seat, if count # >= 4 => it becomes L else nothing
|
||
|
|
if ($adjacent_seats['#'] >= 4) {
|
||
|
|
$new_seats[$row][$col] = 'L';
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return $new_seats;
|
||
|
|
}
|
||
|
|
|
||
|
|
function countOccupiedSeats($seats)
|
||
|
|
{
|
||
|
|
$occupied_seats_count = 0;
|
||
|
|
foreach ($seats as $row) {
|
||
|
|
$row_values = array_count_values($row);
|
||
|
|
$occupied_seats_count += array_key_exists('#', $row_values) ? $row_values['#'] : 0;
|
||
|
|
}
|
||
|
|
return $occupied_seats_count;
|
||
|
|
}
|
||
|
|
|
||
|
|
function seatsAreIdentical($seats, $new_seats)
|
||
|
|
{
|
||
|
|
foreach ($seats as $row_i => $row) {
|
||
|
|
foreach ($row as $cell_i => $cell) {
|
||
|
|
if ($new_seats[$row_i][$cell_i] !== $cell) {
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
|
||
|
|
function displaySeats($seats)
|
||
|
|
{
|
||
|
|
foreach ($seats as $row) {
|
||
|
|
echo implode('', $row). "\n";
|
||
|
|
}
|
||
|
|
echo str_repeat('=', count($seats[0]))."\n";
|
||
|
|
}
|
||
|
|
|
||
|
|
$new_seats = [];
|
||
|
|
$count_loop = 0;
|
||
|
|
while (true) {
|
||
|
|
$new_seats = makeARound($seats);
|
||
|
|
if (seatsAreIdentical($seats, $new_seats)) {
|
||
|
|
echo sprintf('%u occupied seats found in %u round', countOccupiedSeats($new_seats), $count_loop);
|
||
|
|
exit;
|
||
|
|
}
|
||
|
|
$seats = $new_seats;
|
||
|
|
$count_loop++;
|
||
|
|
}
|