Function sp_blockchain::lowest_common_ancestor

pub fn lowest_common_ancestor<Block: BlockT, T: HeaderMetadata<Block> + ?Sized>(
    backend: &T, 
    id_one: Block::Hash, 
    id_two: Block::Hash
) -> Result<HashAndNumber<Block>, T::Error>

Get lowest common ancestor between two blocks in the tree.

This implementation is efficient because our trees have very few and small branches, and because of our current query pattern: lca(best, final), lca(best + 1, final), lca(best + 2, final), etc. The first call is O(h) but the others are O(1).