reimplement euler001 as infinite list processing

youknowone · Mar 27, 2011 · 318a61c · 318a61c
1 parent ca00c5e
commit 318a61c
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diff --git a/euler001.cycle.hs b/euler001.cycle.hs
@@ -0,0 +1,14 @@
+
+module Main where
+
+import System.IO
+
+sum3_5 0 = 0
+sum3_5 n
+	| n `mod` 3 == 0 = n + sum3_5(n-1)
+	| n `mod` 5 == 0 = n + sum3_5(n-1)
+	| otherwise = sum3_5(n-1)
+
+main :: IO()
+main =  do
+	print (sum3_5 999)
diff --git a/euler001.hs b/euler001.hs
@@ -1,14 +1,9 @@
 
-module Main where
+sum3_5 n = [x|x <- [1..], mod x 3 == 0 || mod x 5 == 0] `sum_to` n
-
+	where
-import System.IO
+	sum_to (x:xs) n
-
+		| x >= n = 0
-sum3_5 0 = 0
+		| otherwise = x + (xs `sum_to` n)
-sum3_5 n
+
-	| n `mod` 3 == 0 = n + sum3_5(n-1)
+main = do
-	| n `mod` 5 == 0 = n + sum3_5(n-1)
+	print $ sum3_5 1000 
-	| otherwise = sum3_5(n-1)
-
-main :: IO()
-main =  do
-	print (sum3_5 999)