53 lines
1.1 KiB
PHP
53 lines
1.1 KiB
PHP
<?php
|
|
|
|
$ids = explode("\n", file_get_contents('input.txt'));
|
|
//$ids = ['FBFBBFFRLR'];
|
|
|
|
$seat_ids = [];
|
|
|
|
function decodeRow($row)
|
|
{
|
|
$min = 1;
|
|
$max = 128;
|
|
|
|
foreach (str_split($row) as $cell) {
|
|
if ($cell === 'F') {
|
|
$max = floor($min + ($max - $min) / 2);
|
|
} else {
|
|
$min = ceil($max - ($max - $min) / 2);
|
|
}
|
|
}
|
|
|
|
return $min - 1;
|
|
}
|
|
|
|
function decodeColumn($column)
|
|
{
|
|
$min = 1;
|
|
$max = 8;
|
|
|
|
foreach (str_split($column) as $cell) {
|
|
if ($cell === 'L') {
|
|
$max = floor($min + ($max - $min) / 2);
|
|
} else {
|
|
$min = ceil($max - ($max - $min) / 2);
|
|
}
|
|
}
|
|
|
|
return $min - 1;
|
|
}
|
|
|
|
foreach ($ids as $id) {
|
|
$encoded_row = substr($id, 0, 7);
|
|
$encoded_column = substr($id, 7);
|
|
$row = decodeRow($encoded_row);
|
|
$column = decodeColumn($encoded_column);
|
|
$seat_ids[] = $row * 8 + $column;
|
|
}
|
|
|
|
sort($seat_ids);
|
|
for ($i = current($seat_ids), $l = end($seat_ids), reset($seat_ids); $i <= $l; $i++) {
|
|
if (!in_array($i, $seat_ids, true)) {
|
|
echo $i;
|
|
}
|
|
} |