Do more problems with implementation tag. You do more problems -> more chance of mistake -> more debugging to do.

Test programs locally by writing brute force-Allows you to find out edge cases, or get counter-case for tempting, but unproven, approaches.

Have a Debug template-Having a method or something which prints out variables in a "readable" format can be helpful to know how program states are changing in a certain scope.

Do problems-Doing lot of problems will help you catch your bugs quickly since you would be aware of the potential locations of the bugs.

• Do Stress Testing.

• Open status page, check submissions with WA verdict and try to come up with a test that will fail this solution. Start doing this with easy DIV.2 A problems, then with harder problems.