Qualification Round: Hall of Mirrors

551 correct small sets and 184 correct large sets. View problem statement or contest analysis.

Languages

C++ (399 sets)
Java (108 sets)
Python (91 sets)
C# (45 sets)
C (25 sets)
Haskell (12 sets)
Ruby (11 sets)
Scala (9 sets)

Javascript (5 sets)
PHP (5 sets)
MATLAB (4 sets)
OCaml (4 sets)
D (3 sets)
Visual Basic (3 sets)
Lisp (2 sets)
AWK (1 set)

Basic (1 set)
Go (1 set)
Lua (1 set)
Pascal (1 set)
Perl (1 set)
Shell (1 set)
Subleq (1 set)
Whitespace (1 set)

China (102 contestants)
Japan (72 contestants)
United States (54 contestants)
Russia (49 contestants)
Poland (19 contestants)
Australia (17 contestants)
Canada (16 contestants)
United Kingdom (15 contestants)
South Korea (14 contestants)
Taiwan (14 contestants)
France (13 contestants)
Germany (12 contestants)
Ukraine (12 contestants)
Belarus (10 contestants)
Hungary (9 contestants)
Netherlands (9 contestants)
Bulgaria (6 contestants)
Hong Kong (6 contestants)
Thailand (6 contestants)

Croatia (5 contestants)
Greece (5 contestants)
India (5 contestants)
Spain (5 contestants)
Sweden (5 contestants)
Argentina (4 contestants)
Israel (4 contestants)
Singapore (4 contestants)
Slovenia (4 contestants)
Switzerland (4 contestants)
Belgium (3 contestants)
Brazil (3 contestants)
Indonesia (3 contestants)
Latvia (3 contestants)
New Zealand (3 contestants)
Slovakia (3 contestants)
Bangladesh (2 contestants)
Colombia (2 contestants)
Czech Republic (2 contestants)

Italy (2 contestants)
Kyrgyzstan (2 contestants)
Norway (2 contestants)
Philippines (2 contestants)
Romania (2 contestants)
Serbia (2 contestants)
South Africa (2 contestants)
Sri Lanka (2 contestants)
... (1 contestant)
Bolivia (1 contestant)
Denmark (1 contestant)
Finland (1 contestant)
Iran (1 contestant)
Kazakhstan (1 contestant)
Mexico (1 contestant)
Moldova (1 contestant)
Mongolia (1 contestant)
Portugal (1 contestant)
Turkey (1 contestant)