I was trying to write below program for ackerman function but it fails (waits too long) for ack(4,1) whereas a recursive C program gives result in 37secs.Can someone pls explain this behaviour and recomend some optimisation.<div><div><br></div><div>------haskell code</div><div>f m n  | m==0 =n+1</div><div>           | n==0 = f  (m-1) 1</div><div>           | otherwise = f (m-1) (f m (n-1))</div><div><br></div><div>Thanks</div><div>Abhishek Kumar</div></div>