algorithms-and-data-structures

Did you ever think what is blur exactly? Generally, the blur means something unclear or something that is hard to see. We can see blur (as an effect) everywhere: you can see the similar effect looking through frosted glass, or just looking on the street through a window in a raining day drinking coffee and feeling blue just for nothing. You can also see blur in so many applications and video games....

You may wonder, “Fenwick what? Which tree???”. Don’t be afraid of the spooky term the idea is pretty innocent. Remember: fear is the path to the dark side. First of all, let’s start with a simple problem: Imagine you have an array a of integers of length n. For the sake of simplicity let’s assume it is a one-dimensional array. You are given 2 values start and finish and your goal is to find a sum of all elements in this array between start and finish....