ogijun · January 30, 2011 20:24
diff --git a/rama.hs b/rama.hs
 -- Ramanujan Numbers:
 -- c.f. http://www.ipl.t.u-tokyo.ac.jp/~onoue/pub/jssst01.pdf
 module Main where
 main = print (take 10 (ramanujan (\(a,b) -> a^3 + b^3)))
 ramanujan f = [(x,y) | (x,y)<- zip s (tail s), f x == f y] where s = fsort f 1
 fsort f k = (k,k) : fmerge f [(k,b) | b<-[k+1..]] (fsort f (k+1))
 fmerge f (x:xs) (y:ys)
  | f x <= f y = x : fmerge f xs (y:ys)
  | otherwise = y : fmerge f (x:xs) ys
	-- Ramanujan Numbers:
	-- c.f. http://www.ipl.t.u-tokyo.ac.jp/~onoue/pub/jssst01.pdf
	module Main where
	main = print (take 10 (ramanujan (\(a,b) -> a^3 + b^3)))
	ramanujan f = [(x,y) \| (x,y)<- zip s (tail s), f x == f y] where s = fsort f 1
	fsort f k = (k,k) : fmerge f [(k,b) \| b<-[k+1..]] (fsort f (k+1))
	fmerge f (x:xs) (y:ys)
	\| f x <= f y = x : fmerge f xs (y:ys)
	\| otherwise = y : fmerge f (x:xs) ys