Welcome to the Introduction to Fenwick Tree!

In the realm of data structures, there are various trees that are widely used, such as binary trees, AVL trees, and red-black trees. However, there is one tree that stands out in terms of its efficiency and effectiveness in solving range query and point update problems: the Fenwick Tree.

What is a Fenwick Tree?

A Fenwick Tree, also known as a Binary Indexed Tree (BIT), is a data structure that allows efficient calculation of prefix sums of an array, as well as updates to individual array elements. It is primarily used to solve problems involving cumulative frequency or cumulative sum calculations.

The Fenwick Tree is particularly useful when we need to perform range queries (such as finding the sum of elements in a given range) and update individual elements in an array efficiently.

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#include <iostream>

using namespace std;

​

int main() {

  // Fenwick Tree implementation

}