Dutch version/Nederlandse versie

**Welcome to WHIZZKIDS '97**

On this website you will find information about the Whizzkids
'97 Contest. This mathematics challenge has been sponsored by **CMG**
(consultants in information technology) and was published by De Telegraaf
(a Dutch newspaper) on September 6, 1997. Deadline for solutions was October
21, and the Awards Ceremony took place on November 27 in Amsterdam. The
problem to be solved has been designed by Jan Karel Lenstra (EUT/CWI),
Emile Aarts (EUT/Philips Research) and co-workers.

Competition was open for everybody, and there was a special
category for **professionals** (i.e., those who are involved in mathematics
and computing science research and teaching).

An English description
of the problem and some explanation of the rules is available on our Eindhoven
website. A complete Dutch description was available, at the time of publication
of the puzzle, at CMG. The problem is
to organize a meeting between parents and teachers, where the length of
the conversations is given, and where the order of the conversations per
parent is almost fixed. The problem contains features of a flowshop, but
it is more general. A description of the parents' requests is given in
following table. A numerical description is obtained from the
numerical requests file.

We received 343 submissions. In some of these some mistakes
were made like overlapping interviews, or solutions not satisfying the
requested order. The contest has been won by Paul Hoogendijk, a professional
who recently obtained his PhD in Computing Science at our Department. He
found a schedule with a length of 469 minutes and a total time of 5241
minutes. Gantt charts displaying the conversations are given in the following
table.

Parents agenda | Teachers agenda |

A numerical description of Pauls solution is given in
file with the best solution found. Note that
this is not necessarily the optimum solution. As far as the first criterion is
concerned, however, we can prove a lower bound of **469**. The proof involves a
branch-and-bound search over all potential schedules of length 468. In this search
19509 nodes are evaluated, and the computations take approximately 65 hours on a
Pentium II, 266 MHz.
The ranking of the top contributors
can be found the **ranking list**. Actually
the professionals did do better than in 1996. Of course students can spend
much more time on the real-life instances of combinatorial problems...

We hope that everyone has enjoyed this puzzle and look forward to a next one.

This page was modified last on: December 23, 1997, by Cor Hurkens (wscor@win.tue.nl)