DATARAKU

See structures. Understand them.

An educational visualization app that lets you UNDERSTAND data structures by watching them — not by reading. Abstract concepts like stacks, queues, trees, and hash tables come alive as animations where the structure itself deforms in response to your operations.

Coming soon App Store Coming soon Google Play

Basics (4)

Pile, connect, arrange — the building blocks

S

Stack

LIFO — push and pop. Feel "last in, first out" through stacking motion.

Q

Queue

FIFO — enqueue and dequeue. Watch the entry and exit ends of a queue.

A

Array

Random access plus the shifting of elements on insert and delete.

L

Linked List

Nodes joined by arrows. Insert and delete rewire the arrows.

Advanced (4)

Branch, climb, jump, connect

T

Tree (BST)

Values drop into place after branching left or right by comparison.

H

Heap

Complete binary tree with up-heap and down-heap motion.

#

Hash Table

Keys travel through a hash function and land in a bucket.

G

Graph

Nodes and edges showing adjacency. Walk an undirected graph with BFS.

Designed for learning

Every decision puts the learning experience first

Ads never interrupt animations

Visualizations are sacred. Banners appear only on structure-selection and explanation screens, never on top of an animation.

Continuous motion, not teleporting

Inserts, moves, and deletes always animate as a smooth deformation so you can see what is happening.

Explanation for every structure

Complexity (access / search / insert / delete), pros and cons, and real-world usage — all in one tap.

iPhone / iPad / Android

Same experience across iOS and Android. Dark color palette designed to be easy on the eyes.

Japanese & English

Automatically switches to match your device language. Built for learners worldwide.

Completely free

Every feature unlocked from day one. No in-app purchases, no subscriptions, no paywalls.

Together with ARURAKU

The second information-systems title of the Raku Series, sibling to ARURAKU (algorithm visualization). Cross-links between the two apps let you learn the "motion of computation" and the "structures that carry it" side by side.

Who is this for

Students learning programming for the first time / Anyone preparing for an IT certification / Engineers who want to re-grasp data structures visually / Curious minds who love watching things move