I need to be able to manipulate a large (10^7 nodes) graph in python. The data corresponding to each node/edge is minimal, say, a small number of strings. What is the most efficient, in terms of memory and speed, way of doing this? A dict of dicts is more flexible and simpler to implement, but I intuitively expect a list of lists to be...
Is there a way of mapping data collected on a stream or array to a data structure or vice-versa? In C++ this would simply be a matter of casting a pointer to the stream as a data type I want to use (or vice-versa for the reverse) eg: in C++ Mystruct * pMyStrct = (Mystruct*)&SomeDataStream; pMyStrct->Item1 = 25; int iReadData = pMyStrct...
Where are good sources of information on binary file layout structures? If I wanted to pull in a BTrieve index file, parse MP3 headers, etc... where does one get reliable information?...
I've been able to find details on several self-balancing BSTs through several sources, but I haven't found any good descriptions detailing which one is best to use in different situations (or if it really doesn't matter). Specifically, I want a BST that is optimal for storing in excess of ten million nodes. The order of insertion of the ...
What are good libraries for C with datastructures like vectors, deques, stacks, hashmaps, treemaps, sets, etc.? Plain C, please, and platform-independent....
What would be the best way to fill a C# struct from a byte[] array where the data was from a C/C++ struct? The C struct would look something like this (my C is very rusty): typedef OldStuff { CHAR Name[8]; UInt32 User; CHAR Location[8]; UInt32 TimeStamp; UInt32 Sequence; CHAR Tracking[16]; CHAR Filler[12];} And wo...
What are the most common problems that can be solved with both these data structures? It would be good for me to have also recommendations on books that: Implement the structures Implement and explain the reasoning of the algorithms that use them Thanks!...
Hi everyone, I am working on a project that requires the manipulation of enourmous matrices, particularly pyramidal summation for a copula calculation. In short, I need to keep track of a relatively small number of values (usually a value of 1, and in rare cases more than 1) in a sea of zeros in the matrix (multidimensional array). A s...
Basically, I've written an API to www.thetvdb.com in Python. The current code can be found here. It grabs data from the API as requested, and has to store the data somehow, and make it available by doing: print tvdbinstance[1][23]['episodename'] # get the name of episode 23 of season 1 What is the "best" way to abstract this data with...
Hi. I have a data structure that represents a directed graph, and I want to render that dynamically on an HTML page. Does anyone know of any javascript code that can do a reasonable job with graph layout? These graphs will usually be just a few nodes, maybe ten at the very upper end, so my guess is that performance isn't going to be a bi...
So I've been poking around with C# a bit lately, and all the Generic Collections have me a little confused. Say I wanted to represent a data structure where the head of a tree was a key value pair, and then there is one optional list of key value pairs below that (but no more levels than these). Would this be suitable? public class Toke...
I would like to filter an array of items by using the map() function. Here is a code snippet: var filteredItems = items.map(function(item) { if( ...some condition... ) { return item; } }); The problem is that filtered out items still uses space in the array and I would like to completely wipe them out. Any idea? ...
Ideally, I'm looking for a templated logical Set class. It would have all of the standard set operations such as Union, Intersection, Etc., and collapse duplicated items. I ended up creating my own set class based on the C# Dictionary<>- just using the Keys. ...
I want a data structure that will allow querying how many items in last X minutes. An item may just be a simple identifier or a more complex data structure, preferably the timestamp of the item will be in the item, rather than stored outside (as a hash or similar, wouldn't want to have problems with multiple items having same timestamp)....
I have a tree encoded in a MySQL database as edges: CREATE TABLE items ( num INT, tot INT, PRIMARY KEY (num) ); CREATE TABLE tree ( orig INT, term INT FOREIGN KEY (orig,term) REFERENCES items (num,num) ) For each leaf in the tree, items.tot is set by someone. For interior nodes, items.tot needs to be th...
I'm looking at the PHP Manual, and I'm not seeing a section on data structures that most languages have, such as lists and sets. Am I just blind or does PHP not have anything like this built in? ...
So far I have encountered adjacency list, nested sets and nested intervals as models for storing tree structures in a database. I know these well enough and have migrated trees from one to another. What are other popular models? What are their characteristics? What are good resources (books, web, etc) on this topic? I'm not only lookin...
I am looking for a lean and well constructed open source implementation of a B-tree library written in C. It needs to be under a non-GPL license so that it can be used in a commercial application. Ideally, this library supports the B-tree index to be stored/manipulated as a disk file so that large trees can be built using a configurable ...
In the vein of programming questions: suppose there's a collection of objects that can be compared to each other and sorted. What's the most efficient way to keep track of the smallest element in the collection as objects are added and the current smallest occasionally removed? ...
We have need for a "rating" system in a project we are working on, similar to the one in SO. However, in ours there are multiple entities that need to be "tagged" with a vote up (only up, never down, like an increment). Sometimes we will need to show all of the entities in order of what is rated highest, regardless of entity type, basica...