Hello everyone, with the help of you guys and helpful blogs, I am able to solve A and B pretty much every time, and most of the time C too(Div >=2 of course).

Here is the problem->Contest #576 Div2 C-MP3

And here is my code->here

For those of you who don't want to see code, here is what I did

-made vector of distinct intensities(which is sorted)

-maintained a freq map for frequency of those intensities

-while the condition of the bits is not satisfied, greedily removed the digits from left and right using two pointers