Project Euler
Project Euler is a collection of challenging computational problems that
include a wide range of mathematical and algorithmic challenges, such as
number theory, combinatorics, and optimization, often requiring efficient
code to find solutions.
Advent of Code
Advent of Code is an annual holiday advent calendar of online programming
puzzles that engage participants in a variety of creative problem-solving
tasks, often involving tasks like data manipulation, algorithm design, and
graph theory.
HackerRank
HackerRank is an online platform offering coding challenges, competitions,
and skill assessments to help individuals practice and improve their
programming skills.