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DeepLogicby Aman

Module 1: Foundations · Lesson 3 of 6

Arrays

Traversal, in-place mutation, prefix sums and the running-aggregate patterns (Kadane's algorithm) that every later topic builds on.

Beginner30 minPublished Aug 8, 2026
4 problems0 videosDifficulty: Easy – Medium

No prior lessons are required — this is a good starting point.

Video coming soon

What you'll learn

  • Reason about time and space complexity of common array operations
  • Recognise when a single-pass running-aggregate solves a problem that looks like it needs nested loops
  • Apply prefix sums to answer range-sum questions in O(1) after O(n) preprocessing

Arrays are the first data structure most interview problems build on: contiguous memory, O(1) index access, and a set of traversal and two-pointer patterns that reappear across every other topic in this course.

Start by being fluent with single-pass and two-pass traversals, then move on to prefix sums and Kadane-style running aggregates before attempting anything with sorting or extra data structures.

Learning tracks

Essential
3
Must Do problems only
Interview Ready
4
Must Do + Recommended
Complete Mastery
4
Every curated problem

Problems

Difficulty
Priority

Showing 4 of 4 problems

#ProblemDifficultyPatternPrioritySourceSolutionVideo
1Two SumEasyHashingMust DoleetcodeArticleComing soon
2Best Time to Buy and Sell StockEasyRunning MinimumMust DoleetcodeArticleComing soon
3Maximum SubarrayMediumKadane's AlgorithmMust DoleetcodeArticleComing soon
4Majority ElementEasyBoyer-Moore VotingRecommendedleetcodeArticleComing soon
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