LeetCode 304 - Range Sum Query 2D Immutable | 2D Prefix Sum Explained in Python

In this video, we solve LeetCode 304: Range Sum Query 2D - Immutable using the 2D Prefix Sum technique. This problem teaches how to answer multiple rectangle sum queries in O(1) time after preprocessing the matrix. We will first understand the problem, then look at the brute force approach, understand why it becomes slow, and then build the optimal solution using 2D prefix sum. Key concepts covered: 1D prefix sum to 2D prefix sum Matrix traversal Rectangle sum queries Inclusion-exclusion logic Index precision with row, column, +1 and -1 Final complexity: Preprocessing Time: O(m × n) Query Time: O(1) Space Complexity: O(m × n) This is an important matrix and prefix sum problem for coding interviews. #leetcode #dsa #python #prefixsum #codinginterview