Brain Teasers Challenge

Installing Go

Go is available at:

Click "Download Go" and select a binary distribution for your platform. Execute the binary and following the instructions.

Downloading the source

With Git (preferred):

The source could be downloaded with Git by executing the following command:

git clone https://github.com/asukakenji/brain-teasers-challenge

As a ZIP via HTTP:

The latest version of the source is available at:

https://github.com/asukakenji/brain-teasers-challenge

Click "Download ZIP" on the right hand side of the screen to download the archive. Unzip the archive to get the source code.

With `go get`:

The source cannot be downloaded with go get. If you attempt to do so, go will complain that local imports are used. Since the packages are not assumed to be fetched from the web and imported into a project other than this challenge, I used import "./lib" instead of a fully-qualified package name like "github.com/asukakenji/brain-teasers-challenge/s1q1/lib".

Source code directory structure

brain-teasers-challenge/
  ├─s1q1/
  │   ├─lib/
  │   │   ├─lib_test.go
  │   │   └─lib.go
  │   ├─main.go
  │   └─README.md
  ├─s1q2/
  │   ├─lib/
  │   │   ├─lib_test.go
  │   │   └─lib.go
  │   ├─main.go
  │   └─README.md
  ├─s2q1/
  │   ├─input.txt
  │   ├─lib/
  │   │   ├─lib_test.go (not yet available)
  │   │   └─lib.go
  │   ├─main.go
  │   └─README.md
  └─s2q2/ (not yet available)
      ├─lib/
      │   ├─lib_test.go
      │   └─lib.go
      ├─main.go
      └─README.md

In the original source, the directory names do not correspond to the section and question numbers in README.md. In my source, the directories are named sMqN/, where M is the section number and N is the question number. Here is the mapping:

Question	Original Directory	My Directory
Section 1 Question 1	1/	s1q1/
Section 1 Question 2	4/	s1q2/
Section 2 Question 1	3/	s2q1/
Section 2 Question 2	2/	s2q2/

Running the source

Please see the README.md in the coresponding directory for further information.

Some points to notice

Go uses uppercase and lowercase to distinguish between public and private functions / methods / fields / etc. The declaration is public if the first letter of the identifier is uppercase; it is private otherwise.
Private declarations are visible only to source code in the same package, and it is the primary means in Go to achieve information hiding.
I also use uppercase for identifiers which collide with a Go keyword (e.g. type and map). I made sure that it does not leak information, because, for instance, the public declaration is enclosed by a private scope.
A goroutine is similar to a thread. Goroutines are executed concurrently, but are a lot more lightweight than threads. They communicate through channels (preferred) and shared variables.
In all my solutions, I tried to reduce the problem into smaller pieces. Functions are designed to focus on a single aspect and are highly testable. They are reusable for solving other problems too. This is in contrast to writing one big function to solve the whole problem, or having several smaller functions which are only usable to one problem (most probably because they use problem-specific parameter / return types).

asukakenji/brain-teasers-challenge