The 6th International Olympiad in Informatics was held in Haninge, Sweden in 1994. There were two competition days (Tuesday and Thursday), separated by one day of rest. Each day the competitors had to solve three problems.

Day 1:
      The Triangle
      The Castle
      The Primes

Day 2:
      The Clocks
      The Buses
      The Circle

Other materials:
      Solutions


Note that the grading model changed at IOI'94 and beyond.
Before IOI 1994, a human evaluator would sit behind the competitor's computer and do the testing manually (enter test data through the keyboard, check the output on the screen). Starting from IOI 1994, an automatic grading process is used, with test input defined in files.