George Lukas george-lukas
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| import qualified Data.PQueue.Prio.Min as PQ | |
| import qualified Data.HashSet as Set | |
| import qualified Data.HashMap.Strict as Map | |
| import Data.Hashable (Hashable) | |
| import Data.List (foldl') | |
| import Data.Maybe (fromJust) | |
| astarSearch :: (Eq a, Hashable a) => a -> (a -> Bool) -> (a -> [(a, Int)]) -> (a -> Int) -> Maybe (Int, [a]) | |
| astarSearch startNode isGoalNode nextNodeFn heuristic = | |
| astar (PQ.singleton (heuristic startNode) (startNode, 0)) |
animatedlew
/ len.hs
Last active
April 16, 2024 14:09
Here are two ways to implement Haskell's length function. One way is to map all the elements to 1, then sum them all up. Another way is to add up each head as you recursively call len' with the tail. The result will be the length of the list.
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| -- Maps each element to a 1, then sums up all the elements | |
| len :: [a] -> Integer | |
| len = sum . map (\_ -> 1) | |
| -- Adds up all the heads (recursively) until the list is empty | |
| len' :: [a] -> Integer | |
| len' [] = 0 | |
| len' (_:xs) = 1 + len' xs | |
| -- Extract into a fold using this technique: [ [] := v, (:) := f ] |