These great challenges are published at https://codingchallenges.fyi by John Cricket Twitter
Checkout the newsletter also here on https://codingchallenges.fyi/
I have started on week 1 in implementing the challenges starting March 2023. Since then John published every week a new challenge.
I love the most the real world applications as Redis, load balancer, webserver, IRC client, json parse, url shortener and more to come ....
I started to use Discort and Twitter and https://github.com/CodingChallegesFYI/SharedSolutions to share my solutions.
I decided to implement it back with Java. I have been working with Java since v1.0 back in 2000 and worked with it professionally for more than 18 years. Then I started with C# and powershell working with Azure Cloud.
Here you can find all my implementation, challenge see: https://codingchallenges.fyi
See also other solutions implemented: https://github.com/CodingChallegesFYI/SharedSolutions
Some feedback and and my personal complexity rating
1 * = simple, 5 ***** = a real challenge
| no | Build Your Own | Link code | Description | Complexity |
|---|---|---|---|---|
| 1 | wc tool | no-1 | very simple tool to get back with Java tooling, pipelines and arg parsing |
1 * |
| 2 | JSON parser | no-2 | this is a great project to implement scanner and parser tried to strong test it with lots of test cases (pos and neg cases) |
2 ** |
| 3 | Compression tool | no-3 | get into the Huffman Encoder/Decoder quite complex binary trees with insertion logic without testcases - no chance to solve this riddle awesome experience John |
2 ** |
| 4 | cut Tool | no-4 | little linux tool. simple and easy | 1 * |
| 5 | Load Balancer | no-5 | invested quite a bit of time for fully dynamic and reliable Round Robin and chaos engineering tests to kill processes |
2 ** |
| 6 | sort Tool | |||
| 7 | Calculator | |||
| 8 | Redis Server | no-8 | this is by far the best challenge I have every implemented learning the redis protocol step by step I extended the challenge with lots of commands |
3 *** |
| this is AWESOME idea by John to implement with this you can really learn a new language I implemented a lot of test cases: I used chatGPT to generate test cases |
||||
| 9 | grep Tool | no-9 | I used just my mobile phone and javascript to implement it had some headache topics with * and folders .... check it out |
1 * |
| 10 | uniq Tool | |||
| 11 | WebServer | no-11 | cool to learn the HTTP1.1 protocol and implement it without support libraries I extended my work to implement Servlet types (static files, rest) with routing |
2 ** |
| 12 | UrlShortener | |||
| 13 | diff Tool | |||
| 14 | shell | |||
| 15 | cat Tool | |||
| 16 | IRC Client | no-16 | great to learn the protocol of IRC massive refactoring from step 2 to step 3 - as supposed I tried to this not to build a scanner but use regexp for the different patterns. finally I must say - I like scanners. without https://regex101.com/ - no chance to implement this type of regexp |
2 ** |
| 17 | memcached server | no-17 | fully functional server with many commands, memory mgmt cmd pattern to plugin more if interested lots of testcases additional memcache client test implement a server and a client Later: try to use consistent hashing for multiple servers |
3 *** |
| 18 | spotify client | |||
| 19 | discort bot | no-19 | configured my own discort server implemented a pluggable cmds not deloyed on a server |
1 * |
| 20 | LinkedIn carousel | |||
| 21 | sed-tool | |||
| 22 | DNS resolver | no-22 | implemented A, cname, mx, txt records resolver does same printout as 'nslookup' can be parametrized to test dns principles default using localhost loopback 127.0.0.53:53 |
3 *** |
| 23 | traceroue | |||
| 24 | realtime chat client and server |
|||
| 25 | NATS server | no-25 | implemented NATS server and client cool challenge |
3 *** |
| 26 | git client | |||
| 27 | rate limiter | |||
| 28 | ntp client | |||
| 29 | scheduling automation app | |||
| 30 | Lisp interpreter | no-30 | implemented full Lisp tokenizer, parser and interpreter implemented > 30 built-ins incl pure function caching for faster execution |
4 **** |
| love Lisp. used it to build first neuronal network with 10 own perceptron (back in 1994) additional idea: build interpreter to build this again |
||||
| 31 | QR Code Generator | no-31 | implemented full spectrum of codes: alpha, byte, kanji with all versions support, quality impl debug support with text canvas |
5 ****** |
| impl regions algorithm of rectangles to impl positioning of bits automatic masking tutorial awesome but some missing tips complexity totally underestimated. testcases are key |
||||
| 32 | Crontab | |||
| 33 | head | |||
| 34 | jq | no-34 | used my json parser from no-2 implemented own parser for jq expressions own json serializer for pretty printing new jq evaluator of the expressions |
2 ** |
| 35 | Google Keep |
| Year | Language | Notes |
|---|---|---|
| 85 | BASIC, Assembler | Back in 1985 I learned to code in BASIC on Sharp 1401 and with MS-DOS in 1985 on my 1st PC 4.77 Mhz, with a Hercules monochrome grafic card, <br/1MB RAM, 20MB Disk :-) and Floppies. And sure got to know Assembly to do all crazy stuff down the low level. |
| 87 | Pascal | With the Apple Macintosh 512e used in highschool I started coding with Pascal by Niklaus Wirth. During an internship I used Pascal to run on an VAX by DEC |
| 89 | Modula-2 | Modula-2 as the successor of Pascal also by Niklaus Wirth and here I started all my private coding |
| 90 | bash | with the usage of UNIX systems at ETHZ I started with scripting |
| 90 | C and C++ | with the first university challenges I touched C and C++ but did not like it. |
| 91 | Oberon, Oberon-2, XOberon | At University ETH Zurich I used to code in Oberon by Niklaus Wirth and Oberon-2 the object oriented extension of Oberon and XOberon at Institute of Robotics. I loved it. |
| 93 | Lisp + Prolog | Beside Oberon we use to code our first Neuronal network with 10 neurons in Lisp and our first knowledge base in Prolog - something completly different but nice. |
| 94 | Smalltalk | At my first business job in 1994 I learned and loved Smalltalk - the real object oriented language. In a private project, I even implemented my own Smalltalk parser, compiler and byte code runtime environment in Oberon based on the architecture and bytecode from A little Smalltalk. I also used Visual-Age Smalltalk in my STA in Dallas, TX, USA in 1999. |
| 2000 | Java | In 2000 I arrived at the WWW finally and I learned Java and JDK 1.x and used Java for more then 18 years in business and private. |
| 2011 | Javascript, NodeJs | During Hackathons I learned to code in Javascript, node.js, Solidy |
| 2014 | Objective-C, Swift, Swift-UI | with winning an innovation award in 2014 I started coding with Apple Objective-c for iPhone and Apple Watch Series 1 and later with Swift and SwiftUI for our winning Hackathon idea m-clippy. |
| 2020 | C# | Coding for my beloved Hololens 1 developer edition I started with Unity and C#. Including Hackathons at Microsoft in Redmond with Principal engineers from the Hololens team. Implement 1st holographic bot called LoloBot. |
| 2021 | Powershell | Then I arrived in the Azure Cloud and used C# and powershell for more than 3 years now. |
| 2023 | Typescript | Now back at OpenAPIs development with Nodejs (nestjs) with typescript |
| 2023 | Back in Java | Now for the Coding challenges I flipped back to Java. Unfortunatly Oberon and Smalltalk are almost dead. |
*** and maybe I forgot many languages I learned beside: German, French and English.
I wanted to thank John Cricket for these challenges and I encourage every Engineer from Junior to Principal to do this. Learn a new language or get back to language you have used to code (as me here in Java).
And also learn to understand real-world applications while writing your own version of it.
thx Lolo