Report on IOI'95

Copied from The Report on the 1995 British Informatics Olympiad

The 7th International Olympiad in Informatics took place at the end of June at Eindhoven in the Netherlands. The competition, which hosts the winners of many national contests, attracted over 200 competitors from 52 different countries. It is far from being an exclusively European affair, with teams from as far afield as Colombia and China.

Great Britain is not a newcomer to the event, but having been unable to attend for the last two years it felt like it at times. This year we picked a team of 5 from the 'British Informatics Olympiad', four of whom were able to attend. We flew into Amsterdam, from where we were taken to the Eindhoven University of Technology (TUE), the main competition site.

For the week of the competition, the IOI took over much of the campus. As well as rooms for the computing a hospitality tent was set up, and many of the students were brought in as guides. Accommodation was at the nearby 'Center Parcs' complex. We were there during an unexpected heat wave (the climate is usually similar to our own), so the cool breezes from the complex's lakes and the swimming pool were much appreciated.

Due to traffic, we arrived too late, unfortunately, on the first day to see the opening ceremony. We thankfully made the post-ceremony dinner, where we were introduced to Philip, our guide for the duration of the competition. One of the aims of the IOI is to make friends, and the dinner gave everyone, both competitors and team leaders, the chance to mingle.

The following day, a Tuesday, was spent on a visit to Amsterdam to let people settle in. This started off with a boat trip on the canals, followed by a walk through the city and a visit to the Rijksmuseum. This was the first of two major cultural tours laid on for us, the second being in between the competition days on Thursday.

The second visit, to Rotterdam, gave a chance to see the harbour (the largest in the world), and then a baseball tournament. In the evening there was a reception at the Provinciehuis hosted by the Royal Commissioner of the North Brabant province. This was then followed by a 'surprise' talk by Edsger Dijkstra on the history of computer science.

Wednesday saw the first day of the competition, and an early start - 5 am - for team leaders. There were three questions set for the first day, two computer based and one written. The first question required the competitors to find the smallest enclosing rectangle that four given rectangles could fit into without overlapping. The second question gave a set of prices and special offers in a shop and wanted the cheapest way of purchasing a set of items. The written question introduced the ideas of semaphores and message passing, and asked some simple questions about a system of users and printers.

The questions were well written, with few ambiguities. English is the language used for the whole competition, and there was no need, as there has been in the past, for an English to English translation. Some other teams had more difficulty. The Dutch version of the written question grew from 2 to 7 pages, hardly surprising when the Dutch for 'communication diagram' takes a line and a half to write.

Marking of the questions also went smoothly. This year saw the use of an automatic evaluator, which mercilessly attacked the solutions with a range of test data. Whatever other pros and cons it might have, it certainly made the marking more painless than in previous years. Effort had also been made to divide the marks, splitting each problem into several tasks, so that the previous IOI's catch phrase of 'Zero Marks' was only seldom heard.

The second day of the competition saw a further three questions. This time there was no written one, but one of the problems was interactive: it had to ask questions about the test data which were interpreted by the evaluation program, running on another computer. The more usual type of programming problem simply takes input from a file.

The first question involved finding words from a large dictionary which maximised Scrabble-like scoring rules. The second question involved finding certain types of points on a graph. Finally the interactive program was a puzzle to deduce a network of wires connected to switches. The maximum number of questions that could be asked was specified, while the programs were pushed to this limit by the automatic evaluator, which responded so as to keep the puzzle as hard as possible.

By Friday evening most competitors knew their score for the competition, and were able to sit back. The weekend saw a science fair held at the university, including stalls from all of the companies involved with the IOI. Two world records were made. On Saturday the competitors took part in the largest computer game in the world - 'Hot Balls'. This consisted of 256 Pentiums connected together, and the impressive sight of a wall of 16x16 monitors. The next day saw the world's largest human computer, built out of around 1000 people.

Sunday was also given over to the science fair, but like most teams we elected to stay in Center Parcs to relax. Later in the afternoon we headed to the Frits Philips Music Centre for the closing ceremony.

Although individuals knew their own scores, and the team leaders knew how many people would get each type of medal, we arrived unaware of the medal boundaries. After a procession of speeches all was finally revealed. We received a gold and a bronze medal, with our gold medallist Patrick Smears coming second in the whole competition, and our bronze medallist Justin Santa Barbara narrowly missing silver. Lev Bishop and David Armstrong, our other competitors, both performed very respectably despite missing medals.

The competition was a great success, both for the week's events and the team's performance. Inevitably there were a few hiccups, but thanks to the hard work of the organisation and the guides everyone involved had a wonderful time!

Richard Forster
Deputy Team Leader of the British delegation