Problems and Puzzles

In this page, you can find a list of web-sites containing interesting problems and puzzles.

Puzzles

• Cut-the-Knot. This page contains many puzzles, together with their mathematical history and many Java applets.
• Eriban Software. In this site you can find Java applets for two interesting puzzles: Dropsession and ADDiction.
• Java and Puzzle World. A collection of Cross Sums, Number Line, Nonogram, Sliding Piece Puzzle, and Number Place puzzles.
• Recreational Mathematics in Eric Weisstein's world of Mathematics
• MathPuzzle is a very nice page devoted to puzzles.
• The University of Alberta GAMES Group. This page contains information about Checkers, Chess, Lines of Action, Awari, Hex, Poker, RoShamBo, Othello, and Sokoban, and AI techniques for developing algorithms for playing these games. You can also find some publications on these games.
• Puzzle Index. This page contains an index of some commercial puzzles.
• ClickMazes is a collection of puzzles.
• Cryptarithm. A collection of cryptarithm puzzles and links.
• LatinSquares. An exciting puzzle based on a combinatorial object called Latin Square.
• William Wu's collection of riddles.
• Nick's Mathematical Puzzles.

Competitions and Problem Archives

• Competition Tasks of International Olympiads in Informatics (IOI).
• ACM Programming Contest World Finals Problems
• ACM ICPC Problem Set Archive This page contains ACM ICPC regionals and finals.
• Problem Set Archive with Online Judge
• Internet Problem Solving Contest (IPSC)
• Correspondence Seminar in Programming is a competition for secondary school students.
• USA Computing Olympiad
• International Competition in the Programming
• Mind Sports monthly programming contest. This contest is a monthly programming contest on the Internet.
• Programmer of the Month (POTM) contest is a contest that is held on the Internet once every couple of months.
• Central European Olympiad in Informatics Problems Archive (1994-1999)
• Harvard ACM Contest Page.
• The Annual Berkeley Programming Contest is a contest for selecting Berkeley ACM team. On this page, you can find the problems of this contest, as well as a few other problems.
• Waterloo Local Programming Contest (1992-1995)
• Bulgarian Competitions in Mathematics and Informatics
• Singapore National Olympiad in Informatics Problem Archive
• The Duke Internet Programming Contest was a programming contest on the Internet from 1990 to 1993.
• Australian Programming Competition (ACS). This page contains ACS'93-95 problems.
• The Denison Spring Programming Contest
• Bits and Chips Programming Contest
• American Computer Science League
• The 5th Baltic Olympiad in Informatics
• British Informatics Olympiad (BIO) Problems
• Ukrainian Olympiad in Informatics (A few problems, hard to understand).
• The Canadian Computing Competition.
• Irish programming competitions. (Most of the problems are simple).
• Daniel Marx's Programming Contest Problems Archive. This page is not updated recently, and most of its problems, except a few problems that are listed under "Other Contests", can be found from other links.
• Mohammad Katoozian's collection of math problems.
• USACO Training program gateway