data-structures

Tree-like queues

I'm implementing a interpreter-like project for which I need a strange little scheduling queue. Since I'd like to try and avoid wheel-reinvention I was hoping someone could give me references to a similar structure or existing work. I know I can simply instantiate multiple queues as I go along, I'm just looking for some perspective by ot...

Data Structure Behind Amazon S3s Keys (Filtering Data Structure)

I'd like to implement a data structure similar to the lookup functionality of Amazon S3. For those of you who don't know what I'm taking about, Amazon S3 stores all files at the root, but allows you to look up groups of files by common prefixes in their names, therefore replicating the power of a directory tree without the complexity of...

What is a faster way of merging the values of this Python structure into a single dictionary?

I've refactored how the merged-dictionary (all_classes) below is created, but I'm wondering if it can be more efficient. I have a dictionary of dictionaries, like this: groups_and_classes = {'group_1': {'class_A': [1, 2, 3], 'class_B': [1, 3, 5, 7], 'class_c': [1, 2],...

How to use C# nested structures to access tree of data

I'm importing some XML to C#, and want to be able to access data from the XML in the form of what I think is a nested structure. (I may be wrong!) What I have in my XML is in the following form: <hardwareSettings initial="true> <cameraSettings width="1024" height="768" depth="8" /> <tiltSettings theta="35" rho="90"> </hardware...

advanced python autovivification

This question is about implementing the full Perl autovivification in python. I know similar questions were asked before and so far the best answre is http://stackoverflow.com/questions/635483/what-is-the-best-way-to-implement-nested-dictionaries-in-python/652284#652284. However, I'm looking to do this: a['x']['y'].append('z') without...

Which data structure(s) to back a Final Fantasy ATB-style queue? (a delay queue)

Situation: There are several entities in a simulated environment, which has an artificial notion of time called "ticks", which has no link to real time. Each entity takes it in turns to move, but some are faster than others. This is expressed by a delay, in ticks. So entity A might have a delay of 10, and B 25. In this case the turn orde...

Modifying C# dictionary value

I'm a C++ expert, but not at all for C#. I created a Dictionary<string, STATS>, where STATS is a simple struct. Once I built the dictionary with initial string and STATS pairs, I want to modify the dictionary's STATS value. In C++, it's very clear: Dictionary<string, STATS*> benchmarks; Initialize it... STATS* stats = benchmarks[item.K...

Why is insertion into my tree faster on sorted input than random input?

Now I've always heard binary search trees are faster to build from randomly selected data than ordered data, simply because ordered data requires explicit rebalancing to keep the tree height at a minimum. Recently I implemented an immutable treap, a special kind of binary search tree which uses randomization to keep itself relatively ba...

Which data structures and algorithms book should I buy?

Possible Duplicate: books/sites to get good at algorithm competitions I know C and C++ and I have some experience with Java, but I don't know too much about Algorithms and Data Structures. I did a search on Amazon, but I don't know what book should I choose. I don't want a book which put its basis only on the theoretic part; ...

Is there a way to open a Zope DB in .Net?

Hi, I need to upgrade an old system based on Zope, I need to be able to export the data to something like SQL Server...does anyone know of a way I can open the Zope DB in .NET or directly export it to SQL Server? Thanks, Kieron ...

Why "Algorithms" and "Data Structures" are treated as separate disciplines?

This question was the last straw; and I've been wondering for a long time about it, Why do people think about "Algorithms" and "Data structures" as about something that can be separated from each other? I see a lot of evidence that they're separated in programmers' minds. they request "Data Structures & Algorithms" books they refer ...

C# Array or Dictionary?

Hi. I wanted to know is C# array has a constant access speed? I need to store 1000 items in static array, that will be initialized during server startup. This array will be used readonly, so there will be no changes to array. Should I use a simple C# array (new MyClass[]) or Dictionary instead. I am really new to C# and trying to unders...

How to iterate on boost::mutable_queue

Hello, I need a priority queue where I can increase or decrease the priority key. So boost::mutable_queue seemed perfect despite the lack of documentation. The problem is that I need to iterate at some point over all the elements in the queue. How can I do that? Or is there an othe data structure that would work (preferably in boost)?...

help with tree-like structure

I've got some financial data to store and manipulate. Let's say I have 2 divisions, with offices in 2 cities, in 2 currencies, and 4 bank accounts. (It's actually more complex than that.) I want to show a list like this: Electronics Chicago Dollars Account 2 -> transactions in acct2 in $ in chicago/electronics ...

C++ stl collections or linked lists

I'm developing a OpenGL based simulation in C++. I'm optmizing my code now and i see throughout the code the frequently use of std:list and std:vector. What is the more performatic: to continue using C++ stl data structs or a pointer based linked list? The main operation that involve std::list and std::vector is open a iterator and loop ...

Java data structure suggestion.

Hi folks, I am a newbie in this field so please excuse my silly mistakes :) So the issue I am facing is: On my webpage, I am displaying a table. For now my issue is concerned with three columns of the table. First is : Area Code Second is : Zone Code Third is: Value The relationship between these three is: ...

Data Structures

There is a large stream of numbers coming in such as 5 6 7 2 3 1 2 3 .. What kind of data structure is suitable for this problem given the constraints that elements must be inserted in descending order and duplicates should be eliminated. I am not looking for any code just ideas? I was thinking of a Self-Balancing BST where we could ad...

Need help with java map and javabean

Hi folks, I have a nested map: Map<Integer, Map<Integer, Double>> areaPrices = new HashMap<Integer, Map<Integer, Double>>(); and this map is populated using the code: while(oResult.next()) { Integer areaCode = new Integer(oResult.getString("AREA_CODE")); Map<Integer, Double> zonePrices = areaPrices.get(areaCode); if(zo...

How do you process a large data file with size such as 10G?

I found this open question online. How do you process a large data file with size such as 10G? This should be an interview question. Is there a systematic way to answer this type of question? ...

Storing Icons and Sql with PHP

So I have a simple Apache with MySql I am developing a PHP app. I have Users Table in my DB. I vant to let them store Icons. My question Is what's the best way of attaching such data as icons (100-250kb's) to DB - Is it beter to store them Inside DB or store them as File and some how attaching links to icons into DB. What's the best way...