Received a coding challenge through HackerRank. I made sure I passed all the test cases and checked against a lot of custom test cases as well just to be sure that I had handled everything and the code was working perfect, very efficiently. But received a reject in just 2 hours saying it did not pass all the test cases. I am pretty sure that was not the reason. I had checked against all the test case there could possibly be and the code ran just fine. So if you guys are not serious about hiring - please do not waste the candidate's time by sending online coding challenges.