This challenge borrows one of the hardest problems from the 2025 International Mathematical Olympiad: consider a 2025×2025 grid of unit squares. You want to place rectangular tiles on the grid (each tile’s sides on grid lines, tiles non-overlapping) so that every row and every column has exactly one unit square left uncovered. What is the minimum number of tiles needed?
This problem stumped more than just AI models — of 630 student contestants, 569 scored zero, and only six earned full marks. Can you do better with your favorite decision modeling or optimization tool (or just pen and paper)?
Send your solutions to DecisionManagementCommunity@gmail.com, or open a pull request to add yours here.