2D Prefix Sum
Extend the Prefix Sum technique to two dimensions — efficiently answer rectangular range sum queries on a 2D grid in O(1) after O(m×n) preprocessing. Includes intuition, dry runs, and multi-language implementations.
Extend the Prefix Sum technique to two dimensions — efficiently answer rectangular range sum queries on a 2D grid in O(1) after O(m×n) preprocessing. Includes intuition, dry runs, and multi-language implementations.
Learn the Prefix Sum technique — a powerful range-query optimization that answers range sum queries in O(1) after O(n) preprocessing. Includes dry runs, complexity analysis, common mistakes, and multi-language implementations.
A comprehensive guide to Segment Trees with visual diagrams, build/query/update operations, lazy propagation, code templates in Python, Java, and C++, and practice problems.