The recording of my computer screen during Google Code Jam 2017 Round 1A.

My solution for C-large runs in ceil(A_k/D), which can be up to 10^9 if D=1. It turns out that it is fast enough for one case, but could not run below 8 minutes for 100 testcases (as you can see in my screencast, it is an interesting race between 8 minutes countdown and my program). I downloaded several correct C-large solutions and they also run as slow as mine, but they parallelized the testcases.

TIL : I should add multithreading libraries into my Codejam template.