I am seeking for your advice: how to improve my skills of figuring out edge cases? I have been facing quite a few WA on 100+, 300+ test cases and each of the times I wasn't able to get what was that edge case by myself. Hence, I am asking you guys for an advice :)
And in particular — what is the edge case here?
This is my submission: https://codeforces.com/contest/264/submission/159610034
This is the problem: https://codeforces.com/contest/264/problem/B
Thank you all for your help!