second :: [Int] -> Int
-- testing 360 combinations of argument values
-- pruning with 0/0 rules
-- 1 candidates of size 1
-- 1 candidates of size 2
-- 2 candidates of size 3
-- tested 3 candidates
second xs  =  head (tail xs)

third :: [Int] -> Int
-- testing 360 combinations of argument values
-- pruning with 0/0 rules
-- 1 candidates of size 1
-- 1 candidates of size 2
-- 1 candidates of size 3
-- 2 candidates of size 4
-- tested 4 candidates
third xs  =  head (tail (tail xs))

sum :: [Int] -> Int
-- testing 3 combinations of argument values
-- pruning with 14/25 rules
-- 2 candidates of size 1
-- 0 candidates of size 2
-- 0 candidates of size 3
-- 0 candidates of size 4
-- 6 candidates of size 5
-- tested 3 candidates
sum []  =  0
sum (x:xs)  =  x + sum xs

product :: [Int] -> Int
-- testing 3 combinations of argument values
-- pruning with 14/25 rules
-- 2 candidates of size 1
-- 0 candidates of size 2
-- 0 candidates of size 3
-- 0 candidates of size 4
-- 6 candidates of size 5
-- tested 8 candidates
product []  =  1
product (x:xs)  =  x * product xs

sum :: [Int] -> Int
-- testing 3 combinations of argument values
-- pruning with 15/26 rules
-- 2 candidates of size 1
-- 0 candidates of size 2
-- 0 candidates of size 3
-- 3 candidates of size 4
-- tested 3 candidates
sum  =  foldr (+) 0

product :: [Int] -> Int
-- testing 3 combinations of argument values
-- pruning with 15/26 rules
-- 2 candidates of size 1
-- 0 candidates of size 2
-- 0 candidates of size 3
-- 3 candidates of size 4
-- tested 5 candidates
product  =  foldr (*) 1

