div2A: Try conversions between bases.
div2B: Solve a simpler version of the problem where Ai + 1 ≠ Ai for all i.
div1A: What are the shortest paths of the vehicles? what's the shorter of those paths?
div1B: Forget about the ceiling function. Draw points (i, A[i]) and lines between them — what's the Lipschitz constant geometrically?
div1C: Some dynamic programming. Definitely not for the exp. score of one person — look at fixed scores instead.
div1D: Compute dif(v) in O(N) (without hashing) and then solve the problem in O(N2). Read my editorial of TREEPATH from Codechef :D.
div1E: Can you solve the problem without events of type 1 or 2? Also, how about solving it offline — as queries on subsets.
What, you thought I'd post solutions? Nope. Read the hints, maybe they'll help you. The solutions will appear here gradually.