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<?php
declare(strict_types=1);
namespace drupol\phpermutations\Generators;
use drupol\phpermutations\GeneratorInterface;
use drupol\phpermutations\Iterators\Combinations as CombinationsIterator;
use Generator;
use function array_slice;
use function count;
/**
* Class Combinations.
*
* @author Mark Wilson <[email protected]>
*/
class Combinations extends CombinationsIterator implements GeneratorInterface
{
* {@inheritdoc}
public function generator(): Generator
return $this->get($this->getDataset(), $this->getLength());
}
* The generator.
* @param array<int, mixed> $dataset
* The dataset
* @param int $length
* The length
* @return Generator<array>
protected function get(array $dataset, $length): Generator
$originalLength = count($dataset);
$remainingLength = $originalLength - $length + 1;
for ($i = 0; $i < $remainingLength; ++$i) {
$current = $dataset[$i];
if (1 === $length) {
yield [$current];
} else {
$remaining = array_slice($dataset, $i + 1);
foreach ($this->get($remaining, $length - 1) as $permutation) {
array_unshift($permutation, $current);
yield $permutation;
drupol /
phpermutations
