# Array Data Structure
Confidence: high
Last verified: 2026-05-22
Generation: human_only


## TL;DR

An array is a contiguous block of memory storing elements of the same type, accessible by index in O(1) time. It is the most fundamental data structure. Dynamic arrays (JavaScript Array, C++ vector) use geometric expansion for amortized O(1) append.

## Core Explanation

Key operations: access O(1), search O(n). Dynamic arrays amortize resizing by doubling capacity. Multi-dimensional arrays stored in row-major (C) or column-major (Fortran). Cache locality makes arrays fast — each cache miss loads 64 bytes (16 ints on 64-bit). Drawbacks: fixed size (static) or expensive resize (dynamic).

## Further Reading

- [Introduction to Algorithms (CLRS)](undefined)
- [Algorithms (4th Edition)](undefined)