Questions tagged [efficiency]
Use this tag in reference to comparing the efficiency of various systems or algorithms, or methods to measure efficiency. Big O notation is more related to complexity, but could affect efficiency.
183 questions
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Should I be using any algorithm to sort/find items, or use a language's built-in ways?
I'm currently a first semester IT student, and I'm wondering if it's better to write my method to find something e.g. in a C# List, or to use any built in method to do these, such as LINQ or .Find or ....
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What is the most efficient way to store this data?
I am in charge of rewriting some old VB code. I understand how it works, but I feel like there is a far-more efficient way to do what they did. I just can't figure out what it is. Here is a contrived ...
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How to scramble a word, keeping first and last characters the same?
I have a task, which is to scramble a single word, whose size is greater than 3 letters.
The scrambled word must not be equal to the original, and the first and last letters of the word must remain ...
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Reading from Memory vs Performing an Operation [closed]
I'm learning to program microcontrollers and am trying to develop good habits:
Suppose I have a set of values which can be calculated based on what is already in memory. As a general rule, is it ...
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Low cost exceptions implementation using metaprogramming [closed]
(preface - boring stuff, feel free to skip down to the implementation details)
I need to provide exception handling to a language I am working on. It "compiles" to a subset of C, and since I ...
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Temporary Variables or Not: Choose CPU Time or RAM? [duplicate]
In a case where multiple variables are set equal to an operation using the result of an other operation, is it best to create a temporary variable for the result of the second operation (this would ...
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Sort a list while putting together or after?
I have to read through an extremely large amount of network data from various log files, and compile relevant information about that data to perform statistical analysis on it (the top communicators, ...
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Difference of efficiency [duplicate]
I'm doing a compiler, and I'm using the System.out.println(); to print assembly;
And the code get bigger, and more complicate to understand. I want to know whats is the difference of efficiency ...
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Identical Databases for Multiple Users Reading Efficiency
Our project utilizes a static database (no writes). With many users we don't actually have a problem per se reading it. If a database "locks" per read request by any user, then would it not be more ...
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How do I avoid having to compute square roots for every element in a data set?
I have a list of points, with floating point coordinates, of which I've computed the square of the Euclidean distance between these points. I have not computed the actual Euclidean distance between ...
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Is it wasteful to create a new database table instead of using enum data type?
Suppose I have 4 types of services I offer (they are unlikely to change often):
Testing
Design
Programming
Other
Suppose I have 60-80 of actual services that each fall into one of the above ...
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Class design, responsibility granulation, efficiency and performance
I am in a design dilemma. I have a set of data that can be interpreted in numerous ways, but I cannot really decide how finely grained should it be. To illustrate it with some simple code:
class Base ...
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Multi-pattern matching
I have a given byte array in C and I need to match it against several byte arrays and return true if there is any match.
I can make various memcmp's but I feel that it is very inefficient.
Do you ...
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Reducing a sequence of array modification operations (insert, sort, replace, remove)
Given a plain array of values, e.g.
["Apple", "Orange", "Banana", "Strawberry"]
and a list of operations from the set of [insert, delete, sort and replace], e.g.
[
{cmd: "insert", index: 2, ...
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What is a good metric for guiding a switch from a prototyping language to a production language? [duplicate]
By "prototyping language", I mean one which was chosen by virtue of it's relative ease of quickly accomplishing the sort of design changes common to prototyping in a particular context. (such as data ...
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Are case-studies an effective way of getting efficiency-focused team members to be willing to trade some efficiency for quality? [closed]
Firstly, this does not suggest that efficiency and quality are in conflict... only that some methods prioritize them differently.
Secondly, this is not a question of whether you agree with Scrum ...
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How do I make this functional DSL written in an imperative language more efficient?
Suppose I create a simple functional Domain-specific language (DSL) using an imperative language, in this case C++. Here is a simple implementation of a DSL that can has the notion of a simple value ...
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Optimizing and caching frequently accessed but rarely updated Tables
My app has some tables that will be rarely updated, probably just once in the beginning and at the system setup. Despite that, they will be frequently accessed. Almost every operation depends on ...
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How to avoid calling String.Replace() in a loop?
I am building a very simple email templating system in C#, and it works amazingly, but I have a personal issue with the way I designed it:
Template looks like this:
Hello {UserName},
Welcome to ....
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Need semi-efficient algorithm for 3-dimensional increasing sequence
I have a set of puzzle challenges for a prototype jigsaw puzzle kit, similar to commercial products offered by Thinkfun and Popular Playthings. I have a candidate list of 300 puzzle challenges and ...
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Handling image and audio files in iOS
Currently I have an iOS app that downloads image and audio files from a server, but each view controller downloads its own set of image and audio files (This is because each view controller needs a ...
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How does modulus work?
I am not asking asking how the mathematical concept of modulus works, or how 20 % 3 == 2 I understand this fine. I'm more curious how the compiler/interpreter determines this. I can think of a very ...
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Single import in a large file vs. multiple imports in smaller files. [Golang]
I'm sure the folks at Google worked long and hard to ensure the programmer wouldn't have to worry about details like this, but I'm curious.
In Go if I have multiple files in the same package, but ...
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Fastest way to determine if a value is in a list?
I'm aware there may not be a good solution to this problem. I'm looking for a fast algorithm that determines whether or not a value (let's say an integer) exists in a set of values, however I need the ...
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IRLBot Paper DRUM Implementation - Why keep key, value and auxiliary buckets separate?
Repost from here as I think it may be more suited to this exchange.
I'm trying to implement DRUM (Disk Repository with Update Management) as per the IRLBot paper (relevant pages start at 4) but as ...
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How would a compiler turn an else-if cascade into a switch?
I don't like switch in C and its descendants. Maybe it's the need for a break or the clumsiness of the syntax requiring a shifting of mental gears, I don't know.
Whatever the reason, I will almost ...
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What is better for scalability for this specific dataset, MongoDB or MySQL?
I have a web app which has users, forms, and volunteers signed up on those forms.
Currently I am using MongoDB and have it setup with a collection for admins, and a collection for forms with ...
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Most efficient LINQ result for Contains() query
I currently use the following:
var result = list.Union(otherList).SelectMany(l => l.children).ToList()
foreach(var child in lotsOfChildren){
something = result.Contains(child)
}
I only use ...
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Comparing path strings against list of rules
I am trying to find a way to enhance a filtering algorithm. I am developing a backup software that enables users to specify custom filters to exclude unwanted files/directories.
Currently when trying ...
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Which way is more efficient for getting the space count?
I have just started reading Cracking the Coding Interview. One of the problems (specifically 1.4) after solving and then looking at the answer made me question the way it is done and decided to post ...
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timed events to modulation of real-time audio
I am new very to audio programming and am having trouble figuring out the right kind of algorithm for converting control events (e.g. like MIDI) to real-time sound genesis with a buffer.
At the ...
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Efficient way to map changes in a filesystem hierarchy
I'm currently working on a project that will enable file searching based on metadata found in the file.
It'll be comprised of 2 parts:
a filesystem crawler that passively scans for changes and ...
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What benefit is there to using recursive binary search over iterative binary search or vice versa?
In a recent assignment for my programming 2 class we tested the efficiency of searches by populating a java ArrayList with 13,040 strings. The sequential search was obviously slower than the binary ...
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Closest Point to Moving Target
I have a target which is constantly moving, and only its current position is ever known. I also have about one hundred objects surrounding it, and for each of these only the current position is known....
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Why are return values from compare functions in many languages defined loosely?
Many languages define that compare functions should return ANY negative value, zero, or ANY positive value. Is there some reason that it shouldn't be clearly defined as -1 0 and 1? Does a wide range ...
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When trying to find out if a number is even or odd: AND 1 or OR 0
I recently learned of the trick for finding out if a binary number is odd or even.
If the last bit in the number is 0, then the number is even. If it ends in a 1, then the number is odd.
In the ...
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Bottleneck performance in ECS
I've been looking into building an entity-component-system. Basically, an entity is just an id wrapped around a struct, components are data belonging to that entity(and reference said id), and systems ...
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(jQuery) What is wrong with methods such as .append?
tl;dr: What is wrong with the efficiency of methods such as .append() and what can be alternatives to this?
Explanation:
Hello everyone. I occasionally have to build A/B tests for websites, which ...
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How does Yahoo's Smush.It work and why doesn't everyone use it?
I've recently come across an application by Yahoo called SmushIt. Apparently it does lossless compression on images. Sometimes the image size is reduced by as much as 90%. This of course has major ...
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Efficiency of C# dictionaries
C# dictionaries are a simple way to find if something exists etc etc. I have a question though on how they work. Let's say instead of a dictionary I use an ArrayList. Instead of using ContainsKey (or ...
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Should I do a different SQL table for user privacy settings or just keep it at the users table?
So I am developing a Web Application and I have some concerns about the database. I use a lot of boolean settings at the user table with the form privacy_allow_1, privacy_allow_that, ...
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How do I efficiently send notifications for different events to different users based on their preferences?
I'm creating a notification system for particular events.
A user can set the criteria that match particular events (ie. New item, changed item, closed item etc) Items have different characteristics (...
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Using action array vs Switch Case [closed]
I have an occasion of code in which I will draw a different set of buttons in a screen (depending on the number of the buttons).
One thought (and my current implementation) is to use an action array ...
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What is more efficient, a single square root or multiple divisions?
Say I make a program that calculates all possible (integral) factors of a certain number that has been input.
Is it theoretically more efficient to check with all integers up to the square root of ...
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How to approach program design with respect to data strucutres and algorimths - is there an equivelant of the OO design process for d.s.'s + algs? [closed]
My applogies for probably the worst written body of text I have produced in my life and many thanks to those willing to plough through it all.
I was (and still am) not able to clearly express what I ...
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Should you avoid adding unecessary stack frames?
I have been working with laravel (PHP) recently, and there is an option when using their fluent ORM to define where clauses using closures. This gives us two, functionally equivalent, ways to specify ...
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When I test out the difference in time between shifting and multiplying in C, there is no difference. Why?
I have been taught that shifting in binary is much more efficient than multiplying by 2^k. So I wanted to experiment, and I used the following code to test this out:
#include <time.h>
#include &...
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Trivially Sortable Encoding for Arbitrary-Precision Decimals
I'm looking for a reasonably(*) space-efficient way to encode arbitrary-precision decimals (e.g. BigDecimal), such that when sorting the bit-pattern of the encodings lexicographically, the numbers ...
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Custom Domain or Attribute Reference Table or Both?
I'm designing my first real database and I'm weighing the pros and cons of how to enforce uniformity in my data. My first option is to create a custom domain and program my UI to only allow certain ...
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Simplicity-efficiency tradeoff
The CTO called to inform me of a new project and in the process told me that my code is weird.
He explained that my colleagues find it difficult to understand due to the overly complex, often new ...
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