Take this with a pinch of salt: B-tree when you’re managing more than thousands of items and you’re paging them from a disk or some slow storage medium. RB tree when you’re doing fairly frequent inserts, deletes and retrievals on the tree. AVL tree when your inserts and deletes are infrequent relative to your retrievals.
Efficient Quadtrees All right, I’ll take a shot at this. First a teaser to show the results of what I’ll propose involving 20,000 agents (just something I whipped up real quick for this specific question): The GIF has extremely reduced frame rate and significantly lower res to fit the 2 MB maximum for this site. … Read more
They are actually quite different. They serve similar purpose (region queries on spatial data), and they both are trees (and both belong to the family of bounding volume hierarchy indexes), but that is about all they have in common. R-Trees are balanced, k-d-trees are not (unless bulk-loaded). This is why R-trees are preferred for changing … Read more
Found the list in a similar question, previously on StackOverflow: Hash Table – used for fast data lookup – symbol table for compilers, database indexing, caches,Unique data representation. Trie – dictionary, such as one found on a mobile telephone for autocompletion and spell-checking. Suffix tree – fast full text searches used in most word processors. … Read more
Consider a data structure composed of a hashtable H and an array A. The hashtable keys are the elements in the data structure, and the values are their positions in the array. insert(value): append the value to array and let i be its index in A. Set H[value]=i. remove(value): We are going to replace the … Read more
Use it whenever you need quick access to the largest (or smallest) item, because that item will always be the first element in the array or at the root of the tree. However, the remainder of the array is kept partially unsorted. Thus, instant access is only possible to the largest (smallest) item. Insertions are … Read more
One advantage that no one else has pointed out is that binary search tree allows you to do range searches efficiently. In order to illustrate my idea, I want to make an extreme case. Say you want to get all the elements whose keys are between 0 to 5000. And actually there is only one … Read more
When to use Pre-Order, In-Order, and Post-Order Traversal Strategy Before you can understand under what circumstances to use pre-order, in-order and post-order for a binary tree, you have to understand exactly how each traversal strategy works. Use the following tree as an example. The root of the tree is 7, the left most node is … Read more
Amit Patel has posted an amazing page on this topic. It’s so comprehensive and wonderful that it needs to be the definitive answer to this question: Hexagonal Grids
There are at least 4 libraries that I am aware of providing lenses. The notion of a lens is that it provides something isomorphic to data Lens a b = Lens (a -> b) (b -> a -> a) providing two functions: a getter, and a setter get (Lens g _) = g put (Lens … Read more