先对数字进行因式分解算法

再过滤结果集中，不符合的结果集。

class Helper

{

public function chechPrime($num)

{

for ($i = floor(sqrt($num)); $i > 1; --$i) {

if ($num % $i == 0) {

return false;

}

}

return true;

}

public function getFactorNumber(array &$result, array &$list, $n, $startFactor)

{

if ($n == 1) {

if (count($list) > 1) {

$result[] = $list;

}

return;

}

for ($i = $startFactor; $i <= floor(sqrt($n)); ++$i) {

if ($n % $i === 0) {

array_push($list, $i);

$this->getFactorNumber($result, $list, $n / $i, $i);

array_pop($list);

}

}

array_push($list, $n);

$this->getFactorNumber($result, $list, 1, $n);

array_pop($list);

}

public function primeFactorNumber($num): array

{

$result = [];

$list = [];

$this->getFactorNumber($result, $list, $num, 2);

array_push($result, [$num, 1]);

$result = array_filter($result, function ($value) {

foreach ($value as $v) {

if (!$this->chechPrime($v)) {

return false;

}

}

return true;

});

return $result;

}

}

$helper = new Helper();

$result = $helper->primeFactorNumber(90);

var_dump($result);