Contest Problems
Practice with problems from programming competitions, mathematical olympiads, and algorithmic challenges.
Three Bank Accounts
Peter has three bank accounts. He can transfer between them, but a transfer must exactly double the recipient's balance. Can he always empty one account?
strategy binary number-theory
Grid Tiling Puzzle
Based on IMO 2025: Place rectangular tiles on a grid so that each row and column has exactly one uncovered square.
puzzle geometry optimization
Sunny Lines Puzzle
Based on IMO 2025 P6: Place lines to cover points in a triangle. A line is 'sunny' if it's not parallel to x-axis, y-axis, or x+y=0.
puzzle geometry lines