DIY: Range Sum Query 2D — Immutable
Understand how to implement the NumMatrix class that computes the sum of elements within a sub-rectangle of a 2D matrix. Learn methods to initialize the matrix and quickly return sums for given regions, preparing you for coding interview questions involving range queries.
We'll cover the following...
We'll cover the following...
Problem statement
Given an m * n matrix, you need to handle multiple queries of the following type:
Calculate the sum of the elements of the matrix inside the rectangle defined by its upper left corner, ...