A Fenwick tree or Binary Indexed Tree is a data structure that can efficiently update elements and calculate prefix sums in a table of numbers. This structure was proposed by Peter Fenwick in 1994 to improve the efficiency of arithmetic coding compression algorithms.
There are situation where we need to execute both update and query operations on an array (typically a number array). Naive solutions may take O(n) time to do a prefix sum search. And when the length of the array get increased this solution will give low performance. BIT can do the...
