4 docs tagged with "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.

The Left and Right Sum Differences problem on LeetCode involves finding the absolute difference between the sum of elements to the left and right of each index in an array.

Curated practice problems for mastering Prefix Sum and Difference Array techniques. Problems are organized by difficulty with hints and approach guidance.

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.