permutations.php

permutations.php

<?php

function get_permutations( array $values ) {
	$n = count($values);
	$rec = function ( array $values, &$ret, $n, array $cur = array() ) use ( &$rec ) {
		if ( $n > 0 ) {

			foreach ( $values as $v ) {

				$newCur = $cur;
				if ( ! in_array( $v, $newCur ) ) {
					$newCur[] = $v;
				}

				$rec( $values, $ret, $n - 1, $newCur );
			}
		} else {
			$ret[] = $cur;
		}
	};

	$ret = array();
	$rec( $values, $ret, $n );

	return array_unique( $ret, SORT_REGULAR );
}