Medusa\Tree\PersistentRedBlackTree::removeIn PHP Метод

    private function removeIn(RedBlackTree $t, $key)
    {
        if ($this->compare($key, $t->key()) < 0) {
            if (!$this->isRed($t->left()) && !$this->isRed($t->left()->left())) {
                $t = $this->moveRedLeft($t);
            }
            $t = new self($t->key(), $t->value(), $t->left()->remove($key), $t->right(), $t->color(), $t->isRoot());
        } else {
            if ($this->isRed($t->left())) {
                $t = $this->rotateRight($t);
            }
            if ($this->compare($key, $t->key()) === 0 && $t->right()->isEmpty()) {
                return self::createEmpty();
            }
            if (!$this->isRed($t->right()) && !$this->isRed($t->right()->left())) {
                $t = $this->moveRedRight($t);
            }
            if ($this->compare($key, $t->key()) === 0) {
                $min = $this->minIn($t->right());
                $t = new self($min->key(), $min->value(), $t->left(), $this->removeMinIn($t->right()), $t->color(), $t->isRoot());
            } else {
                $t = new self($t->key(), $t->value(), $t->left(), $t->right()->remove($key), $t->color(), $t->isRoot());
            }
        }
        return $this->balance($t);
    }