SEARCH KEYWORD -- Divide and conquer
Find max subarray of an array
In computer science, the maximum subarray problem is the task of finding the contiguous subarray within a one-dimensional array of numbers (containing at least one positive number) which has the largest sum. For example, for the sequence of values −2, 1, −3, 4, −1, 2, 1, −5, 4; the contiguous subarray with the largest sum is 4, −1, 2, 1, with sum 6. The problem was first posed by Ulf Grenander of Brown University in 1977,...
Max Subarray, Divide and conquer,Kadane 2013-04-22 11:50:35
Implementation of +,-,*,/ with bitwise operator
There is a question asked on Stackoverflow : Divide a number by 3 without using *,/,+,-,% operators. This question is an Oracle interview question. Some people give excellent answers. You can go there and take a look. Usually we need to use bitwise operators to do this kind of implementations. Here I want to show you ways to implement +,-,*,/ with bitwise operators. A bitwise operation operates on one or more bit patterns or binary numerals at the level of their individual bits. It is a fast, pr...
Bitwise operator,Shift,Add,Subtract,Multiplication,Division 2012-08-05 01:52:47
Gcd Algorithm with JavaScript
How to find the greatest common divisor between two integers? We may encounter this problem frequently in interviews or other occasions. An efficient metho to find gcd is the Euclidean algorithm, which uses the division algorithm in combination with the observation that the gcd of two numbers also divides their difference: divide 48 by 18 to get a quotient of 2 and a remainder of 12. Then divide 18 by 12 to get a quotient of 1 and a remainder of 6. Then divide 12 by 6 to get...
JavaScript,Algorithm,Gcd,Implementation, 2011-09-21 15:57:32
Traditional recursion vs Tail recursion
Recursion is a frequently adopted pattern for solving some sort of algorithm problems which need to divide and conquer a big issue and solve the smaller but the same issue first. For example, calculating fibonacci accumulating sum and calculating factorials. In these kinds of issues, recursion is more straightforward than their loop counterpart. Furthermore, recursion may need less code and looks more concise. For example, let's calculate sum of a set of numbers starting with 0 and st...
ALGORITHM,RECURSION,TAIL RECURSION,TRADITIONAL RECURSION 2016-09-23 23:54:09
Easy Parallel Processing in PHP
The proliferation of multicore CPUs and the inability of our learned CPU vendors to squeeze many more GHz into their designs means that often the only way to get additional performance is by writing clever parallel software. One problem we were having is that some of our batch processing jobs were taking too long to run. In order to speed the processing, we tried to split the processing file into half, and let a separate PHP process run each job. Given that we were using a dual core serv...
PHP,Parallel processing,Multithreading like,Sleep 2011-12-12 10:58:59
How does Base64 work
Base64 is a data encoding scheme used in safe data transfer such as HTTP and its extensions. Base64 encoding can conver arbitrary group of bytes into a sequence of readable ASCII characters. These converted characters can safely put in a HTTP header without causing any problem while the peers process the HTTP header. Base64 encoding was invented as part of the MIME content transfer encoding. It is similar to other encoding schemes such as Uuencode and BinHex but with higher efficiency....
A simple example of git bisect command
git bisect is a very powerful command for finding out which commit is a bad commit when bug occurs. The rationale behind this command is that it pin locates the bad commit by divide and conquer. It divides the commit history into two equal parts, then determines whether the bad commit is at the first half or at the other half. This process will continue until the bad commit is located. Here is a really good example created by bradleyboy, this is a simple git repository which demonstr...
GITHUB,GIT,GIT BISECT 2019-07-12 10:31:51
Dividing any number By 9, 90, 900 and so on
The technique for Dividing any number by 9 mentally is simply to reduce a complex division to a very simple addition. The technique can be applied from both ends i.e. from right-most digit or from left-most digit. Dividing by 9 into a mixed number from right-most digit uses the Divisibility Rules for 9: 1. First, add all the digits together and divide by 9, keeping in mind the whole number and the remainder. 2. Write the remainder o...
The Wasteful Legacy of Programming as Language
A few years ago I visited a friend who is a graduate student in linguistics. After some time he asked me if I was aware of the work by Chomsky on formal languages. I told him that yes, Chomsky work was a basis for much of the developments in theoretical computer science. More than that, I was glad to learn that there was something technical that I could share and discuss with other people in linguistics. At the time I found this was just a great coincidence. It was only recently, though, t...
Programming language,Human language,Chomsky 2011-11-28 10:36:34
Implementing DESede/ECB/NoPadding cipher algorithm in GoLang
By default, GoLang doesn't provide the ECB mode cipher for DESede though there is CBC mode provided. In cases we need to encrypt/decrypt data with ECB mode, we need to implement those by ourselves. This mode is frequently used when encrypting/decrypting PIN block which is small block data less than 16 bytes. In this post, we will introduce how to implement the DESede/ECB/NoPadding algorithm in GoLang by using the existing cipher support. Here we will not cover how DESede works in detail, instead...
RECENT
- Oval engagement rings from MoonOcean: Elegance of form and individual approach
- Hologres vs AWS Redshift
- GoLand connect to Hologres
- A journey to investigate a goroutine leakage case
- Understanding Slice Behavior in Go
- Breaking Barriers: How 3D Printing is Democratizing Product Development
- The Power of Efficiency: 10 Practical Energy-Saving Tips for Tech Startups
- Connect to SQLite using Go on Windows
- Break down defer statements in GoLang
- Rust vs Go: how to choose the best programming language for your project?
- more>>