Data Structures and Algorithms
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100% free · TypeScript · four weeks

Data Structures and Algorithms

Data structures and algorithms are how a program stores values and the steps it uses to work on them. This course is 100% free. You read a short lesson, write the function in TypeScript, and find out at once whether it holds.

datastructuresandalgorithms.com

Nothing to buy
The course is 100% free

Nineteen lessons. One exercise each. An editor, tests, stars, and a progress page that stays on your account.

No trial period, no card, and no lesson held back for a paid plan.

What you get

A month of practice for people who already write TypeScript and want the structures under the code they ship.

100% free

All nineteen lessons, the editor, the tests, and your progress. No trial, no card, and nothing locked behind an upgrade.

One idea per lesson

Each lesson is short enough to finish in a sitting. You leave with a function you wrote, not a playlist you half watched.

A desk, not a video

The lesson and a TypeScript editor open side by side. Flip the split horizontal when you want the editor underneath.

Tests on every exercise

Public examples show the shape of the answer. Hidden tests check the cases that are easy to forget. You see the result when you submit.

Stars that mean something

Three stars if the first submission passes, two if it passes within three tries, one if it passes later. The best score stays on the lesson.

Yours when you come back

The account keeps your code, stars, and a note on the topics that still need a pass. Light and dark mode stay with the browser.

Four weeks of course material

Basics first, then the structures, then the patterns. Work in order. A lesson is complete when its exercise passes.

Week 1

Foundations

Learn to name the cost of a loop, then practice the scans you will reuse all month.

  • The cost of a loop
  • Arrays
  • Hash maps
  • Two pointers
  • Sliding window
Week 2

Core structures

Build the structures interviews expect, and a sort you can explain out loud.

  • Linked lists
  • Stacks
  • Queues
  • Recursion
  • Binary search
  • Merge sort
Week 3

Trees and graphs

Walk hierarchical data, keep a priority queue, and search a graph.

  • Trees
  • Binary search trees
  • Heaps
  • Graphs
Week 4

Patterns

Finish with the patterns that turn a hard problem into a smaller one.

  • Greedy choices
  • Backtracking
  • Dynamic programming
  • Tries

How a lesson goes

The coding desk is built for a computer, where the lesson and the editor can sit open together.

01

Read the lesson

A few minutes on the idea, with the cost and the trade stated in plain language.

02

Write the function

TypeScript checking runs as you type. The starter is already in the editor.

03

Submit and keep the score

The tests run immediately. A pass marks the lesson done and stores the stars.

Questions about data structures and algorithms

Short answers, kept in the open so you can read them before you sign up.

01

Is this data structures and algorithms course free?

Yes. The course is 100% free. Creating an account, the nineteen lessons, the editor, the tests, and saved progress do not cost anything. There is no paid tier.

02

What are data structures and algorithms?

Data structures and algorithms are how a program stores values and the steps it uses to work on them. A structure is the arrangement, such as an array, hash map, tree, or graph. An algorithm is the procedure, such as a search, a sort, or a traversal.

03

How do I learn data structures and algorithms?

Learn data structures and algorithms by writing them. This 100% free course is four weeks of TypeScript: read the lesson, implement one function, and submit it against tests. A first passing attempt earns three stars.

04

Which data structures and algorithms does the course cover?

The path covers complexity, arrays, hash maps, two pointers, sliding windows, linked lists, stacks, queues, recursion, binary search, merge sort, trees, binary search trees, heaps, graphs, greedy choices, backtracking, dynamic programming, and tries.

05

Who is this data structures and algorithms course for?

It is for people who already write TypeScript and want the structures and algorithms used in interviews and production code, without a semester of theory first. The coding desk is meant for a laptop or desktop.

100% free

Sign up. The whole course is yours.

Week one is a single pass over an array. The rest of the month builds on it. Nineteen lessons, the editor, the tests, and your progress. Nothing to pay for.