spec.out

sum :: [Int] -> Int
-- testing 3 combinations of argument values
-- looking through 1/9 candidates of size 1
-- looking through 2/5 candidates of size 2
-- looking through 2/8 candidates of size 3
-- looking through 2/10 candidates of size 4
-- looking through 5/16 candidates of size 5
-- looking through 10/29 candidates of size 6
-- looking through 23/56 candidates of size 7
-- looking through 46/114 candidates of size 8
-- looking through 92/228 candidates of size 9
-- looking through 189/465 candidates of size 10
sum xs  =  if null xs then 0 else head xs + sum (tail xs)

(++) :: [Int] -> [Int] -> [Int]
-- testing 3 combinations of argument values
-- looking through 2/9 candidates of size 1
-- looking through 2/8 candidates of size 2
-- looking through 6/18 candidates of size 3
-- looking through 18/42 candidates of size 4
-- looking through 38/102 candidates of size 5
-- looking through 110/262 candidates of size 6
-- looking through 334/746 candidates of size 7
-- looking through 1018/2170 candidates of size 8
-- looking through 2966/6442 candidates of size 9
-- looking through 8662/19142 candidates of size 10
-- looking through 26166/57090 candidates of size 11
xs ++ ys  =  if null xs then ys else head xs:(tail xs ++ ys)