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  1. import Control.Arrow
  2.  
  3. cross ((ax, ay), (bx, by), (cx, cy)) = 
  4.     (bx - ax) * (cy - ay) - (cx - ax) * (by - ay)
  5.  
  6. groupInPairs (a:b:xs) = scanl (curry $ first snd) (a, b) xs
  7. triangulate = uncurry (map . (uncurry . (,,))) . (head &&& groupInPairs . tail)
  8. task = (/ 2) . sum . map (abs . cross) . triangulate
  9.  
  10. main = print $ task [(0, 0), (0, 1), (1, 1), (2, 0)]
  11.  
Success #stdin #stdout 0.01s 3680KB
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1.5
https://ideone.com/R1HQn
language:
Haskell (ghc 8.4.4)
created:
14 years ago
visibility:
public

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