fragmentary ideas ䷿ intellectual what-nots ䷷ and haskell programming ䷴

In my boredom, I implemented the toy sorting algorithm called Gnome Sort. It accomplishes backtracking by using a zipper-like system of two lists treated as stacks, and is about 100X slower than GHC’s merge sort on the test I used. It’s also not especially small or simple-looking. It’s basically terrible:

gnomeSort :: (Ord a)=> [a] -> [a]
gnomeSort = sort [] 
      where sort rs     []     = rs 
            sort []     (x:xs) = sort [x] xs
            sort (r:rs) (x:xs) 
                   | x > r     = sort rs (x:r:xs)          
                   | otherwise = sort (x:r:rs) xs

The above doesn’t keep track of where it left off before it began to backtrack, an obvious optimization which turned the algorithm into an insertion sort:

import Data.List (insert)

insertSort :: (Ord a)=> [a] -> [a]
insertSort = sort [] 
       where sort rs []     = rs 
             sort rs (x:xs) = sort (insert x rs) xs

about 60X slower than Data.List.sort
.