Comment by esafak
2 days ago
Finding the k points closest to the origin (or any other point) is obviously the k-nearest neighbors problem. What algorithm and data structure you use does not change that.
https://en.wikipedia.org/wiki/Nearest_neighbor_search
edit: If you want to use a heap, the general solution is to define an appropriate cost function; e.g., the p-norm distance to a reference point. Use a union type with the distance (for the heap's comparisons) and the point itself.
true, I am thinking, Node and neighbors, this is a heap problem, it actually does matter what algorithm you use, I learn that the hard way today, trying to implement quickselect vs using a heap library (I didn't know you could do that) is much easier, don't make the same mistake!