Use LRANGE with LTRIM in a pipeline. The pipeline will be run as one atomic transaction. Your worry above about WATCH, EXEC will not be applicable here because you are running the LRANGE and LTRIM as one transaction without the ability for any other transactions from any other clients to come between them. Try it … Read more
A data structure is an abstract description of a way of organizing data to allow certain operations on it to be performed efficiently. For example, a binary tree is a data structure, as is a Fibonacci heap, AVL tree, or skiplist. Theoreticians describe data structures and prove their properties in order to show that certain … Read more
This may not be the answer to your problem but it was to mine: http://mediainfo.sourceforge.net/ (It has a library and it’s open source so you can just check for the part(s) you need)
All file systems are different, so there are a huge number of data structures that actually get used in file systems. Many file systems use some sort of bit vector (usually referred to as a bitmap) to track where certain free blocks are, since they have excellent performance for querying whether a specific block of … Read more
Information on this topic is now available on Wikipedia at: Search data structure +———————-+———-+————+———-+————–+ | | Insert | Delete | Search | Space Usage | +———————-+———-+————+———-+————–+ | Unsorted array | O(1) | O(1) | O(n) | O(n) | | Value-indexed array | O(1) | O(1) | O(1) | O(n) | | Sorted array | O(n) … Read more
The asymptotic complexity is sometimes misleading. In the case for Van Emde Boas tree the constant is quite large see here. I quote: However, for small trees the overhead associated with vEB trees is enormous: on the order of 2^(m/2) There are also other cases where an algorithm with better complexity exists but it only … Read more
E is the set of all edges in the graph, as G={V,E}. So, |E| is count of all edges in the graph. This alone should be enough to convince you that the overall complexity can’t be |V| times |E|, since we are not iterating over all the edges in the graph for each vertex. In … Read more
Rust tries to ensure memory safety by forbidding you from doing things that might potentially be unsafe. Since this analysis is performed at compile-time, the compiler can only reason about a subset of manipulations that are known to be safe. In Rust, you could easily store either a reference to the parent (by borrowing the … Read more
Linked List: Item(1) -> Item(2) -> Item(3) -> Item(4) -> Item(5) -> Item(6) -> Item(7) Binary tree: Node(1) / Node(2) / \ / Node(3) RootNode(4) \ Node(5) \ / Node(6) \ Node(7) In a linked list, the items are linked together through a single next pointer. In a binary tree, each node can have 0, … Read more
That’s a big topic! Most has been explained elsewhere, so I won’t try to write a book chapter right here. Instead: Real World Haskell, ch 25, “Performance” – discusses profiling, simple specialization and unpacking, reading Core, and some optimizations. Johan Tibell is writing a lot on this topic: Computing the size of a data structure … Read more