Yoanm\CommonDSA\Factory\NAryTreeFactory::fromLevelOrderList()

Complexity

Conditions	6
Paths	4

Size

Total Lines	29
Code Lines	16

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	16
CRAP Score	6

Importance

Changes	1
Bugs	0	Features	0

<?php
    public static function fromLevelOrderList(array $list, callable $nodeCreator): ?Node
    {
        $tailIdx = count($list) - 1;
        if ($tailIdx < 0 || (0 === $tailIdx && null === $list[0])) {
            return null;
        }

        /** @var \SplQueue<Node> $queue */
        $queue = new \SplQueue();

        $root = call_user_func($nodeCreator, $list[0]); // @phpstan-ignore argument.type
        $queue->enqueue($root);

        $idx = 2; // Should be index 1, but it contains the null value indicating end of children for "root" level !
        while ($idx <= $tailIdx) {
            $parentNode = $queue->bottom(); // =peek() => next value to dequeue from a SplQueue!

            // Append children to the current parent node until a null value is found
            if (null !== $list[$idx]) {
                $parentNode->children[] = $node = call_user_func($nodeCreator, $list[$idx]);
                $queue->enqueue($node);
            } else {
                // Drop current parent node as there is no more children to attach
                $queue->dequeue();
            }
            ++$idx;
        }

        return $root;
    }