Just the popular ones now but 10 years ago, they were really novel. Leetcode, Hacker Rank and of course, the best one is Advent of Code. https://adventofcode.c

Just the popular ones now but 10 years ago, they were really novel. Leetcode, Hacker Rank and of course, the best one is Advent of Code. https://adventofcode.com/ https://adventofcode.com/