Change filenames based on TheAlgorithms#319 (TheAlgorithms#320)

* docs: based on TheAlgorithms#319, all files changed to lowercase without '_' except for '_test.go' files

* update go.mod version to go 1.17

* update golangci-lint version to v1.42.0

* update go-version to 1.17

* update contributing guidelines

* add list from directory.md into readme.md

* Delete DIRECTORY.md

Co-authored-by: Christian Clauss <[email protected]>
Co-authored-by: Andrii Siriak <[email protected]>

CONTRIBUTING.md

@@ -15,13 +15,13 @@ Welcome to [TheAlgorithms/Go](https://github.com/TheAlgorithms/Go)! Before submi
 Being a contributor at The Algorithms, we request you to follow the points mentioned below:
 
 - You did your own work.
-    - No plagiarism allowed. Any plagiarized work will not be merged.
+  - No plagiarism is allowed. Any plagiarized work will not be merged.
 - Your work will be distributed under the [MIT License](https://github.com/TheAlgoritms/Go/blob/master/LICENSE) once your pull request has been merged.
 - Please follow the repository guidelines and standards mentioned below.
 
 **New implementation** New implementations are welcome!
 
-You can add new algorithms or data structures which are **not present in the repository** or that can **improve** the old implementations (**documentation**, **improving test cases**, removing bugs or in any other resonable sense)
+You can add new algorithms or data structures that are **not present in the repository** or that can **improve** the old implementations (**documentation**, **improving test cases**, removing bugs, or in any other reasonable sense)
 
 **Issues** Please avoid opening issues asking to be "assigned” to a particular algorithm. This merely creates unnecessary noise for maintainers. Instead, please submit your implementation in a pull request, and it will be evaluated by project maintainers.
 
@@ -33,7 +33,7 @@ You can add new algorithms or data structures which are **not present in the rep
 - Make sure the file extensions should be `*.go`.
 - Use meaning variable names.
 - Use standard library inside your code and avoid to import packages from other repositories
-- If an implementation of the algorithm already exists, please refer to the [file-name section below](#new-file-name-guidelines).
+- If an implementation of the algorithm already exists, please refer to the [filename section below](#new-file-name-guidelines).
 - You can suggest reasonable changes to existing algorithms.
 - Strictly use snake_case (underscore_separated)  in filenames.
 - If you have added or modified code, please make sure the code compiles before submitting.
@@ -55,6 +55,13 @@ You can add new algorithms or data structures which are **not present in the rep
 - If you find an algorithm or document without tests, please feel free to create a pull request or issue describing suggested changes.
 - Please try to add one or more `Test` functions that will invoke the algorithm implementation on random test data with the expected output.
 
+### Benchmark
+
+- Make sure to add examples and benchmark cases in your `filename_test.go` or `filename_bench.go` if you want separated test and benchmark files.
+- If you find an algorithm or document without benchmarks, please feel free to create a pull request or issue describing suggested changes.
+- Please try to add one or more `Benchmark` functions that will invoke the algorithm implementation.
+- For running the benchmark, you could use this command `go test -bench=.` for more details, read this article [Using Subtests and Sub-benchmarks](https://go.dev/blog/subtests)
+
 #### Typical structure of a program
 
 ```go
@@ -66,8 +73,9 @@ You can add new algorithms or data structures which are **not present in the rep
 // description containing links, references,
 // math equations, etc.
 // author(s) [Name](https://github.com/handle), [Name](https://github.com/handle)
-// see related_file.go, another_file.go, file_test.go
+// see relatedfile.go, anotherfile.go, file_test.go
 
+// ** Is just an example of how to write description for package and function and other stuff ... **
 
 // Package sort provides primitives for sorting slices and user-defined
 // collections.
@@ -78,13 +86,13 @@ package sort
 // name2 package : Add one line description here
 // ...
 import (
-	...
+   ...
 )
 
 
 // Fprint formats using the default formats for its operands and writes to w.
 // Spaces are added between operands when neither is a string.
-// It returns the number of bytes written and any write error encountered.
+// It returns the number of bytes written, and any write error encountered.
 func Fprint(w io.Writer, a ...interface{}) (n int, err error) {
     ...
 }
@@ -94,17 +102,21 @@ func Fprint(w io.Writer, a ...interface{}) (n int, err error) {
 
 #### New File Name guidelines
 
-- Use lowercase words with ``"_"`` as a separator
+- Use lowercase words without ``"_"`` for the file name
+- Use ``"_"`` as a separator only for `_test.go` or `_bench.go`
 - For instance
 
 ```markdown
 MyNewGoFile.GO       is incorrect
-my_new_go_file.go    is correct format
+my_new_go_file.go    is incorrect
+mynewgofile.go       is the correct format
+mynewgofile_test.go  is the correct format
 ```
 
 - It will be used to dynamically create a directory of files and implementation.
 - File name validation will run on Docker to ensure validity.
-- If an implementation of the algorithm already exists and your version is different from that implemented, please use incremental numeric digit as a suffix. For example: if `binary_search.go` already exists in the `search` folder, and you are contributing a new implementation, the filename should be `binary_search2.go` and for a third implementation, `binary_search3.go`.
+- If an implementation of the algorithm already exists and your version is different from that implemented, please use incremental numeric digit as a suffix. For example: if `binarysearch.go` already exists in the `search` folder, and you are contributing a new implementation, the filename should be `binarysearch2.go` and for a third implementation, `binarysearch3.go`.
+- Check out `Go` [Package names](https://go.dev/blog/package-names) roles
 
 #### New Directory guidelines
 
@@ -125,17 +137,17 @@ some_new_fancy_category         is correct
 - It is recommended to keep your changes grouped logically within individual commits. Maintainers find it easier to understand changes that are logically spilled across multiple commits. Try to modify just one or two files in the same directory. Pull requests that span multiple directories are often rejected.
 
 ```bash
-git add file_xyz.go
+git add filexyz.go
 git commit -m "your message"
 ```
 
 Examples of commit messages with semantic prefixes:
 
 ```markdown
-fix: xyz algorithm bug
-feat: add xyx algorithm
-test: add test for xyz algorithm
-docs: add comments and explanation to xyz algorithm
+fix: XYZ algorithm bug
+feat: add XYZ algorithm
+test: add test for XYZ algorithm
+docs: add comments and explanation to XYZ algorithm
 ```
 
 Common prefixes:
@@ -147,7 +159,7 @@ Common prefixes:
 
 ### Pull Requests
 
-- Checkout our [pull request template](https://github.com/TheAlgorithms/Go/blob/master/.github/PULL_REQUEST_TEMPLATE/pull_request.md
+- Check out our [pull request template](https://github.com/TheAlgorithms/Go/blob/master/.github/PULL_REQUEST_TEMPLATE/pull_request.md
   )
 
 #### Building Locally
@@ -162,9 +174,9 @@ go build .
 #### Code Formatter
 
 - Installation (only needs to be installed once.)
-    - Mac (using home-brew): `brew install go`
-    - Windows (MSYS2 64-bit): `choco install golang` [Chocolatey Package Manager](https://chocolatey.org/)
-    - Linux (Debian): `sudo apt-get install golang`
+  - Mac (using home-brew): `brew install go`
+  - Windows (MSYS2 64-bit): `choco install golang` [Chocolatey Package Manager](https://chocolatey.org/)
+  - Linux (Debian): `sudo apt-get install golang`
 - Running (all platforms): `go run main.go` or `go build main.go`
 
 #### GitHub Actions