OJ Board

Thank you very much, indeed.

Well I mean prob B and D.
http://acm.uva.es/contest/data/next/problemset/
B:
"Given two patterns, you are to find a phrase that matches both."
So how come for the input:
<a> b
c <a>

Output is
c b

D:
"is called antiarithmetic if there is no subsequence of it forming an arithmetic progression of ...