RPI solutions

RPI was solved using F# by 4 contestants. Solution sizes: average 2100 bytes (shortest: 2049; longest: 2139).

1292.

Lanfeust (S) (2049 B)
2888.

LOST (S, L) (2091 B)
3076.

lightstar (S, L)
4304.

gradbot (S, L) (2139 B)