+39 +40

3 files changed, 13 insertions, 0 deletions

diff --git a/H35.hs b/H35.hs
index 1d96e4e..caa59c0 100644
--- a/H35.hs
+++ b/H35.hs
@@ -1,5 +1,6 @@
 module H35
 (   primeFactors
+,   primes
 ) where
 
 primeSift (x:xs) = (x:) $ primeSift $ filter ((/=0).(`mod` x)) xs
diff --git a/H39.hs b/H39.hs
new file mode 100644
index 0000000..08da249
--- /dev/null
+++ b/H39.hs
@@ -0,0 +1,3 @@
+import H35
+
+primesR a b = dropWhile (<a) $ takeWhile (<=b) primes
diff --git a/H40.hs b/H40.hs
new file mode 100644
index 0000000..448d372
--- /dev/null
+++ b/H40.hs
@@ -0,0 +1,9 @@
+import H35
+
+goldbach :: Integer -> (Integer, Integer)
+goldbach x = sepToSum x primes $ reverse $ takeWhile (<x) primes
+    where 
+        sepToSum n hhs@(h:hs) tts@(t:ts)
+            | h+t > n = sepToSum n hhs ts
+            | h+t < n = sepToSum n hs tts
+            | otherwise = (h,t)