count :: A -> [A] -> Int
-- testing 13 combinations of argument values
-- pruning with 1/2 rules
-- looking through 0 candidates of size 1
-- looking through 1 candidates of size 2
-- looking through 0 candidates of size 3
-- looking through 0 candidates of size 4
-- looking through 1 candidates of size 5
-- tested 2 candidates
count x xs  =  length (filter (x ==) xs)

count :: A -> [A] -> Int
-- testing 13 combinations of argument values
-- pruning with 8/13 rules
-- looking through 2 candidates of size 1
-- looking through 2 candidates of size 2
-- looking through 0 candidates of size 3
-- looking through 0 candidates of size 4
-- looking through 2 candidates of size 5
-- looking through 10 candidates of size 6
-- looking through 20 candidates of size 7
-- looking through 54 candidates of size 8
-- looking through 130 candidates of size 9
-- looking through 298 candidates of size 10
-- looking through 629 candidates of size 11
-- tested 875 candidates
count x []  =  0
count x (y:xs)  =  count x xs + (if x == y then 1 else 0)