Priority Queue Heapify

Question

Is there any way to initialize priority queue with some elements in O(N) complexity? Using the heapify algorithm possibly.

I searched about that problem but couldn't find a solution. Also, I'm aware of make_heap(), but it's another thing and not about priority queues.

Answer 1

Is there any way to initialize priority queue with some elements in O(N) complexity?

Yes; std::priority_queue<...> has a constructor for this. https://en.cppreference.com/w/cpp/container/priority_queue/priority_queue gives this example:

std::vector<int> vec={3, 1, 4, 1, 5};
std::priority_queue<int> c3(std::less<int>(), vec);

which initializes c3 to a priority queue (max-heap) containing the elements of vec.