+++ /dev/null
-import "Prelude"\r
-\r
-data Poly a = Poly [a]\r
-\r
-normalize l = go (length l)\r
- where\r
- go i = if i > 0 && l!(i-1)==zero\r
- then go (i-1)\r
- else take i l \r
-\r
-instance (Eq a, Additive a) => Additive (Poly a) where\r
- zero = Poly []\r
- Poly a + Poly b = \r
- Poly ( \r
- normalize (\r
- zipWith (+) a b + \r
- if la > lb\r
- then drop lb a\r
- else drop la b\r
- )\r
- )\r
- where\r
- la = length a\r
- lb = length b \r
-\r
-instance (Eq a, Ring a) => Ring (Poly a) where\r
- one = Poly [one]\r
- neg (Poly l) = Poly (map neg l)\r
- a - b = a + (neg b)\r
- Poly a * Poly b = \r
- Poly ( if aDeg < bDeg\r
- then [ segSum n 0 n | n <- [0 ..aDeg] ]\r
- + [ segSum n 0 aDeg | n <- [aDeg+1..bDeg] ]\r
- + [ segSum n (n-bDeg) aDeg | n <- [bDeg+1..sumDeg] ]\r
- else [ segSum n 0 n | n <- [0 ..bDeg] ]\r
- + [ segSum n (n-bDeg) n | n <- [bDeg+1..aDeg] ]\r
- + [ segSum n (n-bDeg) aDeg | n <- [aDeg+1..sumDeg] ]\r
- )\r
- where \r
- aDeg = length a - 1\r
- bDeg = length b - 1\r
- sumDeg = aDeg + bDeg\r
- segSum n low high = sum [ a!i * b!(n-i) | i <- [low..high] ]\r
- fromInteger x = Poly [fromInteger x]\r
- \r
-a = Poly [4.0,5.0,8.0,3.0,2.0,1.0]\r
-b = Poly [1.0,0.0,2.0,1.0]\r
-main = a * a + a * b + b * a + b * b - (a+b)*(a+b)\r
---\r
-[]
\ No newline at end of file