gistfile1.hs

--Implements Mergesort

mergeLists :: (Ord a) => [a] -> [a] -> [a] -> [a]
mergeLists acc xa xb
	| null xa && null xb 		= acc --We are complete
	| null xa					= mergeLists (acc:(head xb)) [] (tail xb) --Only b left
	| null xb					= mergeLists (acc:(head xa)) (tail xa) [] --Only a left
	| (head xa) <= (head xb)	= mergeLists (acc:(head xa)) (tail xa) xb --a first
	| otherwise					= mergeLists (acc:(head xb)) xa (tail xb) --b first