How to Validate ISBN-10 numbers in Golang
The challenge
ISBN-10 identifiers are ten digits long. The first nine characters are digits 0-9. The last digit can be 0-9 or X, to indicate a value …
Technical Articles
In-depth guides, insights, and best practices for modern software engineering
How to Create a Java GUI App that shows the Logged-in User and Hostname
Create a new file called Application.java and paste the following:
import javax.swing.*;
import java.net.InetAddress;
import …How to view a Terraform Module’s Output
An output in Terraform is a way to view the result of an action that has been performed, or resource that has been created.
Let’s say that you …
Read Article →How to Count the Characters in Python
The challenge
The goal of this challenge is to write a function that takes two inputs: a string and a character. The function will count the number of …
Read Article →How to Install Cuda driver for Nvidia on Ubuntu
If you have just upgraded Ubuntu on your AWS g4dn instance and need to install/reinstall Cuda drivers for your Nvidia chipset, then you can run the …
Read Article →How to List all Running Services on Ubuntu
If you need to view a list of all the services that are either running or stopped (or both) on an Ubuntu server, then you can use the following …
Read Article →[Solved] conflict: unable to remove repository reference in Docker
If you get the following error while trying to delete an image in Docker:
Error response from daemon: conflict: unable to remove repository reference …
How to Upgrade an Ubuntu Server
Upgrading an Ubuntu Server is quite easy, just follow the below commands:
Option 1: Tldr; (just run the below!)
sudo apt-get update && sudo …How to Solve Two-Sum in Java
The challenge
Write a function that takes an array of numbers (integers for the tests) and a target number. It should find two different items in the …
Read Article →How to Sort the Gift Code in Java
The challenge
Santa’s senior gift organizer Elf developed a way to represent up to 26 gifts by assigning a unique alphabetical character to each …
Read Article →How to get the Numericals of a String in Java
You are given an input string.
For each symbol in the string if it’s the first character occurrence, replace it with a ‘1’, else replace …
Read Article →How to Replace Noun Phrases with Pronouns in Golang
The challenge
A Noun Phrase is a phrase that can be replaced by a pronoun [he/she/it].
For example, in the sentence:
a girl ate the cookie
“A …
Read Article →Maximum Positive Integer Rotations in Golang
The challenge
Write function MaxRot(n) which given a positive integer n returns the maximum number you got doing rotations similar to the above …
How to “Dashatize It” in Java
The challenge
Given a variable n,
If n is an integer, Return a string with dash'-'marks before and after each odd integer, but do not begin or end the …
How to create a Nickname Generator in Python
The challenge
Write a nickname generator function, nicknameGenerator that takes a string name as an argument and returns the first 3 or 4 letters as a …
Comparing Array Multiplicities in Java
The challenge
Given two arrays a and b write a function comp(a, b) (orcompSame(a, b)) that checks whether the two arrays have the “same” …
How to Find the Sum of Angles in Golang
The challenge
Find the total sum of internal angles (in degrees) in an n-sided simple polygon.
N will be greater than 2.
The solution in Golang
Option …
Read Article →How to Find the Max Tree Node Value in Java
The challenge
You are given a binary tree. Implement the method findMax which returns the maximal node value in the tree.
For example, the maximum in …
Read Article →How to String Search with a Wildcard in Java
The challenge
The method below is the most simple string search algorithm. It will find the first occurrence of a word in a text string.
haystack = …
How to get the AWS AccountID in Terraform
If you are automating AWS resources in Terraform, then you will want to not hardcode things as much as possible.
Terraform makes it possible to pull …
Read Article →Error creating AppStream Fleet – InvalidRoleException
If you get the following error when trying to run some Terraform:
error creating Appstream Fleet (): InvalidRoleException: AppStream 2.0 encountered …
How to Create AWS AppStream resources in Terraform
AWS AppStream has finally made its way into the Terraform AWS Provider.
If you are using hashicorp/aws version 3.67 or above, then you can do the …
How to Stop a Goroutine in Golang
It’s possible to stop a Goroutine by sending a value into it via a signal channel:
exit := make(chan bool)
go func() {
for {
select …How to Create an Empty Branch in Git
If you need to create an empty branch in git, you can follow one of the below options.
If you are using git version 2.27 or newer, then follow the …
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