Topcoder SRM Challenge phase: how to find bugs in code

I have participated over 150 SRMs (Single Round Algorithmic Match) in Topcoder. An important phase during a SRM is to find bugs in other coders code and challenge them with a critical input that you define or create. So far I challenged 68 times in my topcoder history with a success rate of 53%. Here I will point out some strategies to successfully challenge anyone’s code in Topcoder (and Codeforces) and earn some guaranteed points before system test. After pointing out each strategy, I will try to provide links for challenges where I created inputs that failed…