How to Keep up the Hoop in Java
The challenge
Alex just got a new hula hoop, he loves it but feels discouraged because his little brother is better than him
Write a program where …
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342 articles about java development, tools, and best practices
Will there be Enough Space in Java
The challenge
Bob is working as a bus driver. However, he has become extremely popular amongst the city’s residents. With so many passengers …
Read Article →How to Swap Node Pairs In Linked List in Java
The challenge
If you are given the head node in a linked list, write a method that swaps each pair of nodes in the list, then returns the head node of …
Read Article →How to Solve ‘Finding Neo’ in Java
The challenge
Neo is somewhere in the Matrix.
public interface Matrix {
public int size();
public int get(int x, int y);
}
You are Morpheus, and …
Read Article →How to Solve a Pandigital Sequence in Java
The challenge
In mathematics, a pandigital number is a number that in a given base has among its significant digits each digit used in the base at …
Read Article →How to Calculate Transport on Vacation in Java
The challenge
After a hard quarter in the office you decide to get some rest on a vacation. So you will book a flight for you and your girlfriend and …
Read Article →Playing with the letter ‘E’ in Java
The challenge
Given String str, return:
- If given String doesn’t contain any “e”, return: “There is no “e”.” …
The Deaf Rats of Hamelin Challenge in Java
The challenge
The Pied Piper has been enlisted to play his magical tune and coax all the rats out of town.
But some of the rats are deaf and are going …
Read Article →How to Find the Next Perfect Square in Java
The challenge
You might know some pretty large perfect squares. But what about the NEXT one?
Complete the findNextSquare method that finds the next …
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 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 “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 …
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 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 = …
Get the Consonant Value in Java
The challenge
Given a lowercase string that has alphabetic characters only and no spaces, return the highest value of consonant substrings. Consonants …
Read Article →Word Values Challenge in Java
The challenge
Given a string "abc" and assuming that each letter in the string has a value equal to its position in the alphabet, our string …
Split and then add both sides of an array together in Java
The challenge
You will receive an array as a parameter that contains 1 or more integers and a number n.
Here is a little visualization of the process: …
Read Article →Sort Words by Position Index in Java
The challenge
Your task is to sort a given string. Each word in the string will contain a single number. This number is the position the word should …
Read Article →How to get the Current Machine Name and Logged In User in Java
It’s very easy to get the current machine name and logged in user using Java.
Get the Currently Logged in User
String username = …How to install GraalVM on Mac
Install GraalVM with Homebrew
Homebrew is the preferred way to install anything on your Mac.
brew install graalvm/tap/graalvm-ce-java17
Install …
Read Article →How to Generate Random Integers with a Range in Java
Java comes with many different ways to generate random integers, even if you need to specify a lower and upper bound to constrain your required value …
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