Anybody took part in NAIPC 2016? Let us discuss the problems here.

Problem set

I cannot understand this question. Can anyone explain to me why the second example gives an output of 4? What is the moving strategy here? Thanks!

I had a weird WA during Round #300 (B) for the test case 415. I used the custom invocation tool and realized that ((int) pow(10, i)) when i=2 is equal to 99 and the number becomes 100 instead of 101. On my machine, the same code passed.