Blog Posts

Boggle Word Checker in Java

March 31, 2021

The challenge Write a function that determines whether a string is a valid guess in a Boggle board, as per the rules of Boggle.


Read More

Build a pile of Cubes in Kotlin

March 30, 2021

The challenge Your task is to construct a building which will be a pile of n cubes.


Read More

Which x for that sum in Kotlin

March 29, 2021

The challenge Consider the sequence U(n, x) = x + 2x**2 + 3x**3 + .


Read More

Reverse the bits in an integer in Java

March 28, 2021

The challenge Write a function that reverses the bits in an integer.


Read More

Invert values in Kotlin

March 27, 2021

The challenge Given a set of numbers, return the additive inverse of each.


Read More

Spring Boot no main manifest attribute, in

March 26, 2021

You have created a ./target/.jar and have tried to run it using java -jar <app>.


Read More

Moduli number system in Kotlin

March 25, 2021

The challenge A number system with moduli is defined by a vector of k moduli, [m1,m2, ···,mk].


Read More

Smallest possible sum in Kotlin

March 24, 2021

The challenge Given an array X of positive integers, its elements are to be transformed by running the following operation on them as many times as required:


Read More

Floating-point Approximation in Kotlin

March 23, 2021

The challenge Given a semi-inclusive interval I = [l, u) (l is in interval I but u is not) l and u being floating numbers (0 <= l < u), an integer n (n > 0) a function f: x (float number) -> f(x) (float number) we want to return as a list the n values:


Read More

Multiplication table in Kotlin

March 22, 2021

The challenge Create an NxN multiplication table, of size provided in parameter.


Read More

Strip Comments in Kotlin

March 21, 2021

The challenge Complete the solution so that it strips all text that follows any of a set of comment markers passed in.


Read More

Experimenting with a sequence of complex numbers in Kotlin

March 20, 2021

The challenge Consider the sequence S(n, z) = (1 - z)(z + z**2 + z**3 + .


Read More

pt-online-schema-change Add Index

March 19, 2021

Percona has a great toolkit that allows you to perform schema changes on a MySQL or MariaDB database without any downtime, it works by creating a new table with the same schema, making the changes to it and applying triggers for insertion, deletion and all updates, all while performing your valuable schema updates for you!


Read More

Sums of Parts in Kotlin

March 18, 2021

The challenge Let us consider this example (array written in general format):


Read More

Diophantine Equation in Kotlin

March 17, 2021

The challenge In mathematics, a Diophantine equation is a polynomial equation, usually with two or more unknowns, such that only the integer solutions are sought or studied.


Read More

Matrix Addition in Java

March 16, 2021

The challenge Write a function that accepts two square matrices (N x N two dimensional arrays), and return the sum of the two.


Read More

Numbers that are a power of their sum of digits in Java

March 15, 2021

The challenge The number 81 has a special property, a certain power of the sum of its digits is equal to 81 (nine squared).


Read More

Integer triangles in Java

March 14, 2021

The challenge You have to give the number of different integer triangles with one angle of 120 degrees which perimeters are under or equal a certain value.


Read More

Minimum path in squares in Java

March 13, 2021

The challenge You’re given a square consisting of random numbers, like so:


Read More

Pascal’s Diagonals in Java

March 12, 2021

The challenge Create a function that returns an array containing the first l digits from the nth diagonal of Pascal’s triangle.


Read More