A — ok.
B — easy. ok.
C — most interesting
D — O(N^2) — precision issue, AC with biginteger / Slower solution — TL issue
E — I don't like this
G — straightforward voronoi
I — input format..
FGHI — TL issue (especially I)
J — see model solution. really?
K — easy. ok.
ICPC WF should keep the level of the problem high. But for this year it seems like a big fail...
Too many problems have issues not related to the core solution.