https://code.google.com/codejam/contest/11274486/dashboard
Simple. Nothing to tell.
For each point, calculate the real height of it.
For points on board, real height equals to its height.
Then, using bfs (with priorityQueue) to calculate
all real heights.
Binary Search. If mid*start>0 then start=mid, else end=mid.
As f(1) and/or f(-1) may be zero, we need to calculate [-1+1e-12, 1-1e-12].
DFS.
For each card, each level, dfs to find the max attack.
Prune if currAtk+maxAtkLeft<=currMaxAtk. That is, if the sum
of attack current and max attacks left is smaller than the max attack
we have found, just return immediately.
Check D.java for more details.