Arrays under the hood

Why reading arr[500] is instant but inserting in the middle is slow. The one idea - contiguous memory - that explains an array's every strength and weakness.

16 min read

Arrays under the hood is part of DSA in Java, visualized

Chapter 1 is free - you've seen how these lessons work. Unlock the full course once and keep it for life, including every chapter still being written.

  • Read any algorithm's Big-O cost on sight, and pick the faster approach
  • Implement the core data structures in Java from scratch, not from memory
  • Recognise the pattern behind an interview problem and reach for the right tool
  • Debug your own code by watching exactly what it does, step by step

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