subset :: [Int] -> [Int] -> Bool
-- testing 44 combinations of argument values
-- pruning with 29/39 rules
-- looking through 2 candidates of size 1
-- looking through 4 candidates of size 2
-- looking through 14 candidates of size 3
-- looking through 40 candidates of size 4
-- looking through 160 candidates of size 5
-- looking through 0 candidates of size 6
-- looking through 448 candidates of size 7
-- looking through 784 candidates of size 8
-- tested 1318 candidates
subset [] xs  =  True
subset (x:xs) ys  =  elem x ys && subset xs ys

subset :: [Int] -> [Int] -> Bool
-- testing 44 combinations of argument values
-- pruning with 3/3 rules
-- looking through 0 candidates of size 1
-- looking through 0 candidates of size 2
-- looking through 2 candidates of size 3
-- looking through 6 candidates of size 4
-- looking through 2 candidates of size 5
-- tested 9 candidates
subset xs ys  =  sort xs `isSubsequenceOf` sort ys