PHP数组迭代以扁平化所有可能的结果

<?php
function flattenArray($array) {
    $result = [];
    foreach ($array as $value) {
        if (is_array($value)) {
            $result = array_merge($result, flattenArray($value));
        } else {
            $result[] = $value;
        }
    }
    return $result;
}

$array = [1, [2, [3, 4], 5], 6];
$flattenedArray = flattenArray($array);
print_r($flattenedArray);
?>

<?php
function flattenArrayIterative($array) {
    $result = [];
    $stack = array_merge([$array], []);

    while (!empty($stack)) {
        $current = array_pop($stack);
        foreach ($current as $value) {
            if (is_array($value)) {
                array_push($stack, $value);
            } else {
                $result[] = $value;
            }
        }
    }

    return $result;
}

$array = [1, [2, [3, 4], 5], 6];
$flattenedArray = flattenArrayIterative($array);
print_r($flattenedArray);
?>