Lets say you coded your solution for a problem and try to submit it, and got WA. How do you debug, specially those problems which is having very very large code. Like this April Long challenge, Factor Tree question, when you submit it you got WA but acc. to you its working fine in local? How to find that mistaked. Do you just simply check examples (hit and try way) first run in local and check by yourself if its right or is there any other way?