Prefix Sum Study Guide

< Return to Home Page

Basic Prefix Sum

Fundamental problems that introduce the concept and basic usage of prefix sums.

• 🟨 238. Product of Array Except Self [Solution]
• 🟨 560. Subarray Sum Equals K [Solution]

Advanced Prefix Sum Techniques

More complex applications of prefix sums, often combined with other concepts.

Prefix Sum with Modular Arithmetic

Problems that combine prefix sums with modular arithmetic for efficient calculations.

• 🟨 523. Continuous Subarray Sum [Solution]

Prefix Sum with HashMap

Problems that use hashmaps in conjunction with prefix sums for optimized solutions.

• 🟨 974. Subarray Sums Divisible by K [Solution]

Problem Difficulty Legend

• 🟩 Easy
• 🟨 Medium
• 🟧 Medium-Hard
• 🟥 Hard
• ⬛ Very Hard

Additional Resources

• Prefix Sum Array – Implementation and Applications
• Range Sum Query - Immutable (LeetCode)
• Prefix Sums Technique (Competitive Programming Algorithms)