This directory contains source code for various data structures and algorithms that are covered in Tampere University of Technology in the course 81120 "Data Structures and Algorithms". Most the material was written by Juha Heinanen, a former professor in our department. He introduced Scheme to this course (then called "Advanced Course in Programming") in 1988. I was his teaching assistant for a couple of years, and when he resigned in 1990, I inherited the course from him, with all the material he had written. I am not certain wether he really wrote all the algorithms, or got them from someone, but I've attributed them to him anyway. There are also some algorithms I have written myself. Most of the code is poorly if at all commented. This is mostly because in the course it is supplemented with the material explaining the algorithms etc. Unfortunately it is all in Finnish. I would really like to see this collection grow into something that would profit other people besides myself, so I'm open to suggestions. Please note that these impelmentations are used for teaching the algorithms, so clarity is preferred over efficiency if the choice has to be made. Please don't hesitate to send comments. suggestions etc. to me! Pertti Kellom\"aki (pk@cs.tut.fi) Tampere Univ. of Technology Software Systems Lab Finland