Congratulations to the Winners of the HIIT Open 2024 Programming Contest

One task solved by many teams asked for the smallest number of triangle numbers whose sum equals the given input. There, the intended solution was to study the pattern on smaller instances to convince oneself that three triangle numbers always suffice, and then to test efficiently if one or two triangle numbers are enough. In one of the harder problems, the task was to find two subsets with equal sums faster than by enumerating all subsets, with the main ideas for the solution being to exploit the pigeonhole principle and partition the elements in two smaller sets. All teams solved at least one of the problems.

The winning team was “Barren plateau” with Topi Talvitie and Olli Hirviniemi, who solved 8 tasks. Similarly, Henrik Aalto (Aalto University), Elias Simojoki (Aalto University), and Valtteri Aurela (Aalto University) from “Aalto CS-A1140 Team 2” managed to solve 8 tasks slightly after the first team, earning them the second place. The third place went to the single-member team “(╯°□°)╯︵ ┻━┻” of Mikko Sysikaski (SisuSoft), who solved 7 tasks.

For more information on the contest, problems, and the results, see https://open.hiit.fi/.