I have multiple parabolas ($y = ax^2 + bx + c$) which may intersect with each other (or some of them may not intersect). I am trying to find upper segments of these parabolas, e.g. bold part in the picture:
I need to find it in $O(n\log n)$. There's a solution for line version of this problem: https://stackoverflow.com/questions/7420193/how-to-find-upper-envelopes-of-intersected-lines-in-onlogn
But I cannot find a way to apply this solution to quadratic version since there are $a$, $b$ and $c$ variables to consider. Any help will be appreciated.