Project Euler

Programs to solve various problems found on Project Euler: https://projecteuler.net

My Project Euler Profile(s)

https://projecteuler.net/profile/cmathsolve.png

https://projecteuler.net/profile/cmath.png

Problem 1

Multiples of 3 or 5

https://projecteuler.net/problem=1

Problem 2

Even Fibonacci Numbers

https://projecteuler.net/problem=2

Project Euler's rules

"I learned so much solving problem XXX, so is it okay to publish my solution elsewhere"?

"The rule about sharing solutions outside of Project Euler does not apply to the first one-hundred problems".

https://projecteuler.net/about#publish

It appears that you have answered your own question. There is nothing quite like that "Aha!" moment when you finally beat a problem which you have been working on for some time. It is often through the best of intentions in wishing to share our insights so that others can enjoy that moment too. Sadly, that will rarely be the case for your readers. Real learning is an active process and seeing how it is done is a long way from experiencing that epiphany of discovery. Please do not deny others what you have so richly valued yourself.

However, the rule about sharing solutions outside of Project Euler does not apply to the first one-hundred problems, as long as any discussion clearly aims to instruct methods, not just provide answers, and does not directly threaten to undermine the enjoyment of solving later problems. Problems 1 to 100 provide a wealth of helpful introductory teaching material and if you are able to respect our requirements, then we give permission for those problems and their solutions to be discussed elsewhere.

Requirements

Python3+
JDK 17+
JRE 17+
C++ Compiler
C compiler

install Python in Windows visit

https://docs.python.org/3/using/windows.html

Check that Python is installed

Open CMD and type python.
If it exists, to see where this executable lives, type where python
If not, follow the instructions for installation at python.org

How to compile and run in Windows (back slash)

python main.py

install Java in Windows visit

https://docs.oracle.com/en/java/javase/18/install/installation-jdk-microsoft-windows-platforms.html#GUID-DAF345BA-B3E7-4CF2-B87A-B6662D691840

Oracle JDK 18.0.2 Installer

https://www.oracle.com/java/technologies/downloads/#jdk18-windows

Oracle JDK 18.0.2 Installer Tutorial

https://docs.oracle.com/en/java/javase/18/install/installation-jdk-microsoft-windows-platforms.html#GUID-DAF345BA-B3E7-4CF2-B87A-B6662D691840

Cygwin Get that Linux feeling - on Windows

https://www.cygwin.com/

Check if you have Linux commands on your Windows machine

Open CMD and type the command, e.g., ls or vim
If it exists, use where to see where it lives, e.g., where ls or where nano
If it does not exist, you will need to install something like Gitbash or CygWin

Install Java (Linux, Ubuntu 20.04)

sudo apt update
sudo apt upgrade
sudo apt install openjdk-17-jdk openjdk-17-jre

How to compile Java in Unix / Linux

javac -d classes/ -cp lib/sample-1.jar src/project/Example.java -verbose -Xlint:unchecked

jar --create --file lib/sample-2.jar -C classes/ .

How to run Java Unix / Linux

java -cp lib/sample-2.jar:lib/sample-1.jar project.Example > output.txt

How to run Java in Windows

java -cp lib/sample-2.jar;lib/sample-1.jar project.Example > output.txt

Update Path Variable in Windows (Access javac, jar, and java commands)

Option 1. 
Open the System Properties and add the paths with the javac, jar, and java executables to your PATH environment variable.
Go to Settings >> System >> About >>  Advanced system settings >> Environment Variables >> System Variables >> Path >> Edit >> New 
copy the paths, e.g., C:\Program Files\Java\jdk-18.0.2.1\bin, into here. Also, consider adding the JAVA_HOME variable to your System Variables while you are in this menu.
Under System Variables select New. In the variable name, type JAVA_HOME (or JRE_HOME for JRE installations). In Variable Value, copy and paste the filepath of your Java installation as shown above,
e.g., "C:\Program Files\Java\jdk-18.0.2.1" or "C:\Program Files\Java\jdk-20". 


Option 2. Excute PATH command. Copy the return string (should have a list of paths semi-colon delimited). Append path to JDK binary and library directors separated by a semi-colon, e.g., 

user> PATH
PATH=C:\Program Files\Common Files\Oracle\Java\javapath;C:\cygwin64\bin

user> PATH C:\Program Files\Common Files\Oracle\Java\javapath;C:\cygwin64\bin;C:\Program Files\Java\jdk-18.0.2.1\lib;C:\Program Files\Java\jdk-18.0.2.1\bin

user> PATH
PATH=C:\Program Files\Common Files\Oracle\Java\javapath;C:\cygwin64\bin;C:\Program Files\Java\jdk-18.0.2.1\lib;C:\Program Files\Java\jdk-18.0.2.1\bin

Maven JUnit (Third Party Package) Repository

https://mvnrepository.com/artifact/junit/junit/4.13.2

Adding Maven JUnit 4.13.2 (Third Party Package) Repo to your environment (Example API Call to Download Repo File(s))

curl -s https://repo1.maven.org/maven2/junit/junit/4.13.2/junit-4.13.2.jar -o C:/JUnit/Junit-4.12.jar

Add JUnit unit testing framework to your Windows Java Development Environment

To add the JUNIT_HOME variable to your System Variables while you are in this menu.
Under System Variables select New. In the variable name, type JUNIT_HOME. In Variable Value, copy and paste the filepath of your Java installation as shown above,
e.g., "C:\JUnit". 

How to compile in Windows (back slash)

javac -d classes/ -cp lib\sample-1.jar src\project\Example.java -verbose -Xlint:unchecked
jar --create --file lib\sample-2.jar -C classes/ .

How to run in Windows (semi-colon)

java -cp lib\sample-2.jar;lib\sample-1.jar project.Example > output.txt

Maven JSON Simple 1.1.1 (Third Party Package) Repo Example

https://repo1.maven.org/maven2/com/googlecode/json-simple/json-simple/1.1.1/json-simple-1.1.1.jar

Adding Maven JSON Simple 1.1.1 (Third Party Package) Repo to your lib directory (Example API Call to Download Repo File(s))

curl -s https://repo1.maven.org/maven2/com/googlecode/json-simple/json-simple/1.1.1/json-simple-1.1.1.jar -o lib\json-simple.jar

Coindesk BTC API endpoint (Example API Call to retrieve JSON payload)

https://api.coindesk.com/v1/bpi/currentprice.json

Sending a Request to Coindesk BTC API endpoint and saving the returned payload

curl -# -o api_payload.json https://api.coindesk.com/v1/bpi/currentprice.json

Maven JSON Simple (Third Party Package) Repo

https://mvnrepository.com/artifact/com.googlecode.json-simple/json-simple/1.1.1

How to compile in Ubuntu (forward slash)

javac -d classes/ -cp lib/sample-1.jar src/project/Example.java -verbose -Xlint:unchecked
jar --create --file lib/sample-2.jar -C classes/ .

How to run in Ubuntu (colon)

java -cp lib/sample-2.jar:lib/sample-1.jar project.Example > output.txt