Data structures and algorithms are the part of coding interviews most people dread. A lot of tutorials start with code. We wanted to start with something you already understand.

Every data structure is something you've seen before

Stack → a pile of plates. You add to the top and take from the top. Last in, first out. That's your browser's Back button and every function call in your program.

Queue → the line at a coffee shop. First come, first served.

Array → a row of numbered lockers. Know the number, walk straight to it.

Hash map → a coat check. The ticket tells you exactly which hook your coat is on.

Linked list → a train. Each car only knows the car behind it.

Tree → a family tree, drawn upside down with the root at the top.

Graph → a subway map. Stations are nodes, tracks are edges.

Binary search → finding a name in a phone book.…