My algorithm problems

Below is the list of problems I authored for various programming competitions.

Polish Olympiad in Informatics

Fibonacci representation (19th Polish Olympiad in Informatics, 2nd stage)
Problem description (PL) Booklet with solution (PL)
Bidding (19th Polish Olympiad in Informatics, finals)
Problem description (PL) Booklet with solution (PL)
Laser (20th Polish Olympiad in Informatics, finals)
Problem description (PL) Booklet with solution (PL)
Trips (22nd Polish Olympiad in Informatics, finals)
Problem description (EN) Booklet with solution (PL)
Beads (23rd Polish Olympiad in Informatics, 1st stage)
Problem description (PL) Video solution (PL)
Digit sum (24th Polish Olympiad in Informatics, 2nd stage)
Problem description (PL)
Fence (25th Polish Olympiad in Informatics, finals)
Problem description (PL)
Taxi (25th Polish Olympiad in Informatics, finals)
Problem description (PL)
Subsequences (26th Polish Olympiad in Informatics, 1st stage)
Problem description (PL) Solution (PL)
Game of divisors (26th Polish Olympiad in Informatics, finals)
Problem description (EN)
Least common multiple (27th Polish Olympiad in Informatics, 1st stage)
Problem description (EN)
Kindergarten (27th Polish Olympiad in Informatics, 1st stage)
Problem description (EN)
Nursery's difficult dillemma (27th Polish Olympiad in Informatics, 2nd stage)
Problem description (PL)
Knapsack packing (28th Polish Olympiad in Informatics, 2nd stage)
Problem description (PL)
Sum of primes (28th Polish Olympiad in Informatics, finals)
Problem description (PL)
Dominoes (29th Polish Olympiad in Informatics, 1st stage)
Problem description (PL)
Coprime numbers (29th Polish Olympiad in Informatics, 2nd stage)
Problem description (PL)
Meteors (29th Polish Olympiad in Informatics, finals)
Problem description (PL)
Scales (29th Polish Olympiad in Informatics, finals)
Problem description (PL)
Treasure (31st Polish Olympiad in Informatics, finals)
Problem description (PL)

Polish Junior Olimpiad in Informatics

The following list is incomplete, I chose only few problems I find interesting.

Even-digit Numbers (14th Polish Junior Olympiad in Informatics, 1st stage)
Problem description (PL) Solution (PL) Video solution (PL)
Number process (14th Polish Junior Olympiad in Informatics, 1st stage)
Problem description (PL) Solution (PL) Video solution (PL)
Unlucky numbers (14th Polish Junior Olympiad in Informatics, 1st stage)
Problem description (PL) Solution (PL)
Zigzag (14th Polish Junior Olympiad in Informatics, 2nd stage)
Problem description (PL) Solution (PL) Video solution (PL)
Speedrun (14th Polish Junior Olympiad in Informatics, 1st stage)
Problem description (PL) Solution (PL) Video solution (PL)
Fences (15th Polish Junior Olympiad in Informatics, 2nd stage)
Problem description (PL) Video solution (PL)
Multiplication (16th Polish Junior Olympiad in Informatics, 1st stage)
Problem description (PL)
Drawing triangles (16th Polish Junior Olympiad in Informatics, finals)
Problem description (PL) Solution (PL)
Number pyramid (17th Polish Junior Olympiad in Informatics, finals)
Problem description (PL) Solution (PL)
Divisibility (18th Polish Junior Olympiad in Informatics, 1st stage)
Problem description (PL)
Polite queue (18th Polish Junior Olympiad in Informatics, 2nd stage)
Problem description (PL) Solution (PL)
Chess figure (19th Polish Junior Olympiad in Informatics, finals)
Problem description (PL)
Spiral (19th Polish Junior Olympiad in Informatics, finals)
Problem description (PL)

Central European Olympiad in Informatics

Cloud Computing (25th Central European Olympiad in Informatics)
Problem description (EN)
Toys (25th Central European Olympiad in Informatics)
Problem description (EN)