Arrays

Contiguous collections of values and the base techniques built on indexed access, scanning, and in-place updates.

Arrays are fixed-order collections stored in contiguous memory, which makes indexed reads fast and predictable. Most interview questions build on scanning, range reasoning, or controlled mutation of that linear layout.

Contiguous collections of values and the base techniques built on indexed access, scanning, and in-place updates.

Mixing up index movement with value movement during in-place updates.

Using extra arrays when a two-pointer or in-place pass is sufficient.

Forgetting that insertion and deletion usually shift later elements.