PHP -如何获取数组/链表中的所有可能序列

function getAllPermutations($array, $prefix = []) {
    $permutations = [];

    // 如果数组为空，则当前排列已经完成，将其添加到结果数组中
    if (empty($array)) {
        $permutations[] = $prefix;
    } else {
        for ($i = count($array) - 1; $i >= 0; $i--) {
            $newArray = $array;
            $currentElement = array_splice($newArray, $i, 1)[0];

            // 递归获取剩余元素的所有排列
            $newPrefix = array_merge([$currentElement], $prefix);
            $permutations = array_merge($permutations, getAllPermutations($newArray, $newPrefix));
        }
    }

    return $permutations;
}

$array = [1, 2, 3];
$allPermutations = getAllPermutations($array);
print_r($allPermutations);

function getAllPermutations($array) {
    $stack = [];
    $permutations = [];
    $stack[] = [$array, []];

    while (!empty($stack)) {
        list($currentArray, $prefix) = array_pop($stack);

        if (empty($currentArray)) {
            $permutations[] = $prefix;
        } else {
            for ($i = count($currentArray) - 1; $i >= 0; $i--) {
                $newArray = $currentArray;
                $currentElement = array_splice($newArray, $i, 1)[0];

                // 将剩余元素和当前元素入栈
                $newPrefix = array_merge([$currentElement], $prefix);
                $stack[] = [$newArray, $newPrefix];
            }
        }
    }

    return $permutations;
}

$array = [1, 2, 3];
$allPermutations = getAllPermutations($array);
print_r($allPermutations);