OJ Board

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Dear all,

here http://www.math.luc.edu/~anh/ACM99/ one can find a very nice class ACMIO for performing input/output in Java. It is written by Dr. Andrew Harrington, a famous person in ACM contests (search in google by "Andrew Harrington"+ACM to find out more about this respectable scientist).

A ...

here is definition, but it's a spoiler too:
http://mathworld.wolfram.com/BinaryBracketing.html

in short: binary bracketing when maximum two 'x' stand next to each other. non-binary when it's not binary, so there is somewhere a 'xxx'.

Better definition: "the number of different ways in which a ...