From d09ec147fa223dcf760eaa592bc0573e678ea412 Mon Sep 17 00:00:00 2001
From: Joe Zhao <ztuowen@gmail.com>
Date: Wed, 1 Apr 2015 12:05:34 +0800
Subject: +39 +40

---
 H35.hs | 1 +
 H39.hs | 3 +++
 H40.hs | 9 +++++++++
 3 files changed, 13 insertions(+)
 create mode 100644 H39.hs
 create mode 100644 H40.hs

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)
-- 
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