I have a list of nine different websites (see them below) that I visit every-single-day to keep my programming skills in shape. I have no preference whatsoever since they are all pretty much the same, some of them have better coding problems than others but nothing special.
However, during the last two months I have been using LeetCode and HackerRank more than the others because they are used I have been interviewing with a lot of medium and big sized companies, the big ones usually ask medium/hard questions from LeetCode while the medium sized companies prefer to filter people via HackerRank.
I discovered leetcode recently and left a drive-by forum comment pointing out an algorithm nobody had considered for one of the problems in the recent-discussion list.
Then I tried out a couple of the beginning problems, selected Python as the language, and discovered that since they apparently port the test cases over without modification from other languages, my Python solutions had to check for integer overflow and return special values in those cases.
I decided then that it's probably not going to be a very reliable measurement for the stuff I do or care about.
I thought Code Fights was the current hotness, people have been hyping how they feature real AIs (testbots) created by actual companies or note. Isn't its format at least distinct from the other sites, which are mostly the same Top Coder format of "here is an algorithmic problem, solve it and we'll grade it?"
CodeFights is more like a play environment like CodingGame, I am yet to find a company that requires me to write the algorithm for a robot in order to demonstrate my programming skills. This is why I prefer LeetCode and HackerRank, not because they are better but because they are what companies are using to interview people. CodingGame has a Machine Learning exercise so it is not like the other websites are not innovating, it is just personal preferences.
However, during the last two months I have been using LeetCode and HackerRank more than the others because they are used I have been interviewing with a lot of medium and big sized companies, the big ones usually ask medium/hard questions from LeetCode while the medium sized companies prefer to filter people via HackerRank.
- https://leetcode.com/
- https://www.codeeval.com/
- https://www.hackerrank.com/
- https://www.hackerearth.com/
- https://www.interviewbit.com/
- https://www.codingame.com/
- https://www.codewars.com/
- https://open.kattis.com/
- https://codefights.com/