# Questions tagged [algorithm]

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### Algorithm to find longest common substring

I'm having a bit of trouble coming up with a general solution to the following problem. First a bit of context. End goal: set file permissions on all files and directories created by a rpm My plan was ...
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1 vote
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### How to calculate monthly loan payment with fixed monthly drawdown

I would like to modify the Excel PMT function to take account of a fixed monthly drawdown on the loan. For example, where the loan is a credit card, the card holder my spend money every month, and ...
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578 views

### Data compression algorithm in chrome and chromium

I was doing some research on browsers and I want to know what is data compression algorithm really mean in browser. and what are algorithm currently using in chrome, and chromium.
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### Why does compression process takes longer than extraction process?

Whenever we compress a file with any method be it zip, rar, 7z, why does compression process takes more time than extraction?
1k views

### Excel Formula for optimizing a route where each row represents a different "station" that can do different things

I was unsure about how to frame this question. Here is a minimum viable example: Jane can do A, B, D. Shes 1km away. Jack can do B, D, F. He is 1.5km away. Marshal can do E, F, A. He is 20km away. ...
64 views

### Do processes stay in memory until completion?

I'm solving a problem in which I'm given several processes, each with it's own required CPU time for completion, memory requirements and time of entry to the ready queue. The algorithm the scheduler ...
73 views

### suppose I have a +1,000,000,000,000,000 entry in my database [closed]

So suppose I have +1,000,000,000,000,000 or more entries in my database! and I am looking for the entry number 1,999,999,999,999,990 wouldn't it take years to get it? Now as a programmer, will I ever ...
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1 vote
54 views

### What determines what algorithms are available to OpenSSH?

Is the version of OpenSSH or the version of OpenSSL (or a combination of the two) that is installed on a given system what determines which Ciphers, KexAlgorithms, and MACs are available to be ...
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### Use ffmpeg for thumbnail selections

This is a follow-up question from HERE. I want to sample k frames out of the n number of frames in a given video using FFMpeg and its thumbnail filter. There is a post here providing some insights how ...
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### What exactly is Excel's Auto Fill algorithm?

What is the algorithm used by Auto Fill in Excel? For example, when I enter the numbers 3,4,5,7,8 into a column and then use Auto Fill, I get the following result: 3 4 5 7 8 9.3 10.6 11.9 13....
71 views

### Will this program terminate for every Integer? [closed]

In a Part Test for GATE Preparation there was a question : f(n): if n is even: f(n) = n/2 else f(n) = f(f(n-1)) I answered "It will terminate for all integers", because even for negative ...
233 views

### Designing a custom small DDoS detection and defense sytem [closed]

Am very new to the topic so I would like some guidance where to get started. What I want is, some tools to programmatically observe network traffic and preform some actions on the traffic. I don't ...
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### Finding permutations of a number using bash script

Is it possible to write a bash script which takes a 4 digit number as an command line argument and produces all permutations of that number with using only pure bash?
1 vote
40 views

### Creating an specific type of meta-algorithm

I need to create a program able to create an algorithm to Matlab. For instance, in this program, I want to give it an integer n>0 and make it create a Matlab algorithm with the following code: u1 = ...
1k views

### How to achieve high-quality downscaling of diagrams (like in Firefox)?

I often need to downscale raster images consisting of thick straight lines and other thick curves, like this one: . Using GIMP 2.8.16 and its various interpolation options to resize the image to ...
1 vote
1k views

### How can I find vendor name from MAC address of my NIC

So far I learned having my first 3 bytes of my MAC address(HEX format: 00:00:00:00:00:00) I can find my NIC's vendor name(which is a string). Can you elaborate this algorithm? No websites/tools links ...
175 views

### How to make an arbitrary Microsoft FILETIME?

I would like to make an arbitrary Microsoft FILETIME. The algorithm is more important than the Microsoft programming language. For example if today is June 2 2016, I would like to calculate the ...
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47 views

### Does such a cache (unreduce) actually exist?

I'm reading about cache replacement algorithms and one states (source, page 37) Def. A reduced schedule is a schedule that only inserts an item into the cache in a step in which that item is ...
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### Allow browser to use more cores

I wrote an algorithm with JavaScript. When I execute it in Google Chrome, it takes about 30min, which is quite long. When I open the task manager during the computation, I can see that Chrome takes ...
61 views

### Is there a piece of software that will help me convert "Hex" code based on already known input and output? [closed]

The title is a little confusing, but the jist of it is this: I have a list of "HexCode" (I use that term loosely as they are not actually hex codes) from both before conversion and after conversion. ...
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451 views

### How to write a VBA code me which displays 10 random numbers between 1 to 50 without a repeat of the numbers

How do I write a VBA code me which displays 10 random numbers between 1 to 50 without a repeat of the numbers?
1 vote
2k views

### How to simplify Excel/Google Sheets formula with redundant method calls?

I have an Excel (Well, technically Google Sheets) workbook containing product inventory warehouse storage information. I figured out how to construct queries so it grabs the needed information from ...
27 views

### Running time of locating a file in a directory

When you search for a file in a directory with a large number of files (n), what is the worst case running time of locating this file? I mean does the OS (linux) sequentially check all filenames in ...
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1 vote
3k views

### What is the hash algorithm for owncloud passwords

I need to know the algorithm used to generate the password hashs that look like this: \$2a\$08\$ztQUBr1vx97Rc9MiJVr05.LZWg92jGYkRFEJViHhfZjaWpB0xfgGu It looks like bcrypt to me but when I hashed my ...
1 vote
185 views

### Wireless Client Algorithm Used to Choose SSID/AP

Does anybody happen to know if it is possible to find (or determine) the actual algorithm that wireless clients use to choose which the BSSID to connect to when there are multiple SSIDs available at ...
190 views

### What is the data structure used by Recycle bin & hows it implemented [duplicate]

In a Windows file system, we cannot created a folder or file with the same name. For example, New Folder. If there is a existing folder already named as "New Folder" and if we create another folder ...
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### Back of the envelope calculation for speed of matrix multiplications [closed]

I'm trying to develop an intuition for how feasible/scalable machine learning algorithms are. The dominant cost is always matrix multiplications, but there seem to be no readily Google-able resource ...
• 131
723 views

### Algorithm/Code for detecting colours in a picture [closed]

Is it possible to have code that can automatically detect the colours in a picture? If so what is this technology? Thanks,
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1 vote
349 views

### Understanding how Native Instruments Traktor analyzes and beat-grids songs

Quick Summary: How does NI Traktor determine: BPM (beats per minute) beat-grid key of song auto-gain Detailed Description: I am very interested in understanding exactly how Traktor analyzes a song; ...
209 views

### When we save a file in windows - is actual location of file on hard disk random or deterministic?

I want to know when we try to save a file to harddisk how the os saves the file to hard disk. Will two computers with same configuration and ALSO SAME INTERNAL STATE save the file on the same location ...
• 245
1 vote
338 views

### How does a Benes network work?

How does a Benes network work? If I have a Benes network with 8 nodes on each side, like this one here: . . . how do I know whether or not I take the upper or lower port of a switch in each stage? ...
1 vote
258 views

### How to unpack a compressed executable without knowing the compression algorithm

I'm not sure if this question was asked. I searched for it and could not find it. How can I unpack a compressed executable without knowing what compression algorithm was used to compress it? For ...
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### A software to draw an algorithm [closed]

I'm currently working on a complex algorithm, and I want to draw it into a reference document. Basically, I have formulas, formulas are linked to their operands, operands are formulas themselves ...
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3k views

### How to transfer data between two networks efficiently

I would like to transfer files between two places over the internet. Right now I have a VPN and I am able to browse, download and transfer files. So my question is not really how to transfer the files;...
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### Scheduling algorithm used in Windows 7

What is the scheduling algorithm used in Windows 7?
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### What algorithms are used in signature and heuristic virus detection? [closed]

I'm trying to write a paper on virus detection techniques. I've downloaded many journals, papers and used many websites. I have found overview definition for both of these terms but I would like to go ...
3k views

### Is there a hashing algorithm that allows me to specify output character length?

My security officer is looking for a hashing algorithm that will take a string of up to 20 characters, and then output a unique, 12-character alphanumeric hash. The 20-character string is generally ...
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907 views

### Deleting music file duplicates but retaining iTunes metadata

Back when I first imported the majority of my iTunes library I had the copy files to iTunes Media folder when adding to library option checked, so basically my whole music library was duplicated on ...
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### What's the fastest way to combine two or more files in Linux?

I want to combine two or more files in Linux, so I am using the following command: cat small_file LARGE_File LARGER_FILE > SUM_OF_FILES However this runs very slow. Does anyone know a Linux tool ...
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### How synchronize two disks (or folders) using symbolic (or hard) links (like rsync)?

I'm searching a tool or a shell script or another program to synchronize two or more folders or disks. But it differs of rsync tool, because, I don't want to duplicate the missing file, but do a ...
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### Encryption algorithm of gnome-keyring

What encryption algorithm does gnome-keyring use? I've tried looking for it on their site but it seems quite hidden.
• 277
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122 views

### Algorithm Of Getting Information From Ip Adress [closed]

i want to know how some sites and some softwares give information from a given ip address?? i mean does it have a specific algorithm?
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### A tool (library, source-code, algo) to select area in an image based on perceived focus plane

Say we have an image in which a human eye can distinctly see several "planes" of focus - a blurry background ("telelens"), the sharp(er) subject (a human, or an object), and again a blurry foreground (...
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### How does SSD garbage collection work?

Correct me if I'm wrong but doesn't the block bitmap (which keeps track of free blocks on a disk drive) vary for different file systems (both location and structure wise)? So how can OCZ have a ...
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### unix sort algorithm implementation

What sorting algorithm(s) is/are used in the unix sort command? Insertion/quicksort/etc.?
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### When erasing freespace, why do utilities write random strings of data?

I've been reading about various utilities that erase the free space on your hard drive, and they all talk about doing multiple passes of writing random strings of 1's and 0's using various algorithms.....
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### How do defragmenting programs work?

a) What algorithm would a typical defragmenting program use to get rid of the fragmentation? b) In Defraggler, I have a quick defrag option and a defrag option. Assuming defrag would do a normal ...
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### Decrypt files encrypted with TrueCrypt

I have a usb pen memory crypted with TrueCrypt. Is there a way to decrypt ( without TrueCrypt ) files encrypted with TrueCrypt in linux ?
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