VisuAlgo was conceptualised in 2011 by Associate Professor Steven Halim (NUS School of Computing) as a tool to help his students better understand data structures and algorithms, by allowing them to learn the basics on their own and at their own pace. Together with his students from the National University of Singapore, a series of visualizations were developed and consolidated, from simple sorting algorithms to complex graph data structures. Though specifically designed for the use of NUS students taking various data structure and algorithm classes (CS1010/equivalent, CS2040/equivalent (inclusive of IT5003)), CS3230, CS3233, and CS4234), as advocators of online learning, we hope that curious minds around the world will find these visualizations useful as well.

Animated visualizations of algorithms (sampling, shuffling, sorting and maze generation).

Animated visualizations of data structures and algorithms.

I’ve been dividing the continent again. Back in the summer of 2000, on a coast-to-coast car trip, I began wondering about the Great Divide, the line that traces the spine of North America, separating the Atlantic and Pacific watersheds. How would you identify that line out on the landscape, or on a topographic map? Eventually I wrote some programs to explore the problem, and then an American Scientist column. The column became a chapter in my book Group Theory in the Bedroom.

Visual Cryptography uses two transparent images. One image contains random pixels and the other image contains the secret information. It is impossible to retrieve the secret information from one of the images. Both transparent images or layers are required to reveal the information. The easiest way to implement Visual Cryptography is to print the two layers onto a transparent sheet.