From 868573fe49fd2b4a3ae42378f6f7b557b15fcb64 Mon Sep 17 00:00:00 2001
From: Jonathan Chan <jonathanhwchan@gmail.com>
Date: Sun, 2 Jul 2017 22:57:36 -0700
Subject: [PATCH] Problem 69

---
 69.hs | 11 +++++++++++
 1 file changed, 11 insertions(+)
 create mode 100644 69.hs

diff --git a/69.hs b/69.hs
new file mode 100644
index 0000000..894a725
--- /dev/null
+++ b/69.hs
@@ -0,0 +1,11 @@
+import Math.NumberTheory.Primes.Factorisation
+import Data.List
+
+ratio :: Integer -> Double
+ratio n = foldr (\(prime, _) acc -> let p = fromIntegral prime in p / (p - 1) * acc) 1.0 $ factorise n
+
+answer :: Integer -> (Integer, Double)
+answer n = let range  = [2, 4..n]
+           in maximumBy (\(i1, r1) (i2, r2) -> compare r1 r2) $ zip range $ map ratio range
+
+main = print $ answer 1000000