The challenge Write a simple CamelCase method for strings. All words must have their first letter capitalized without spaces. Example: The solution in Java code… Read More »CamelCase Method in Java

The challenge Create a function that takes an integer as an argument and returns “Even” for even numbers or “Odd” for odd numbers. The solution… Read More »Even or Odd in Java

The challenge You need to square every digit of a number and concatenate them. For example, if we run 9119 through the function, 811181 will… Read More »Square Every Digit in Java

The challenge You are given a string of numbers in sequence and your task will be to return the missing number. If there is no… Read More »Simple number sequence in Java

The challenge Create a function taking a positive integer as its parameter and returning a string containing the Roman Numeral representation of that integer. Modern… Read More »Roman Numerals Encoder in Java

The challenge The action of a Caesar cipher is to replace each plaintext letter (plaintext letters are from ‘a’ to ‘z’ or from ‘A’ to… Read More »First Variation on Caesar Cipher in Java

The challenge The first century spans from the year 1 up to and including the year 100, The second – from the year 101 up to and including the year 200, etc.… Read More »Century From Year in Java

The challenge You have a positive number n consisting of digits. You can do at most one operation: Choosing the index of a digit in the number, remove this… Read More »Find the Smallest Number in Java

The challenge You are given a non-null array of integers. Implement the method arrayToTree which creates a binary tree from its values in accordance to their order,… Read More »Convert Array to Tree in Java

The challenge You will have a list of rationals in the form where all numbers are positive ints. You have to produce a result in… Read More »Common Denominators in Java

The challenge Given a positive number n > 1 find the prime factor decomposition of n. The result will be a string with the following… Read More »Primes in Numbers in Java

The challenge The maximum sum subarray problem consists in finding the maximum sum of a contiguous subsequence in an array or list of integers: Easy… Read More »Maximum subarray sum in Java

The challenge Let’s implement the Luhn Algorithm, which is used to help validate credit card numbers. Given a positive integer of up to 16 digits, return true if… Read More »Validate Credit Card Number in Java

The challenge There is an array with some numbers. All numbers are equal except for one. Try to find it! It’s guaranteed that array contains… Read More »Find the unique number using Java

The challenge You are given an array (which will have a length of at least 3, but could be very large) containing integers. The array… Read More »Find The Parity Outlier in Java

The challenge Write a method that takes an array of consecutive (increasing) letters as input and that returns the missing letter in the array. You… Read More »Find the missing letter using Java

The challenge Write a function that takes a string of braces, and determines if the order of the braces is valid. It should return true if the… Read More »Determine the order of braces is valid using Java

The problem It may happen to you that when you try and pull some Java dependencies, you will get the annoying PKIX path building failed:… Read More »Solved: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

The challenge Given an array of integers, find the one that appears an odd number of times. There will always be only one integer that… Read More »How to Find the odd int in Java

The challenge Write a function that will return the count of distinct case-insensitive alphabetic characters and numeric digits that occur more than once in the input string.… Read More »Count the number of Duplicates in Java

The challenge In this challenge, you will be given an integer n and your task will be to return the largest integer that is <= n and has… Read More »Calculating Simple Max Digit Sum in Java

The challenge After a long conflict, the rulers of Nek and Glo have decided that a final duel should decide the fate of their countries.… Read More »The String Combat Challenge in Java

The challenge Pig Latin is an English language game where the goal is to hide the meaning of a word from people not aware of… Read More »Solving Single Word Pig Latin in Java

The challenge Little Annie is very excited for upcoming events. She want’s to know how many days she have to wait for a specific event.… Read More »Count the Days in Java

If you are using a HashMap to keep a running total of a series of elements, then you often need to increment a HashMap item,… Read More »Java HashMap Create or Increment Value