From 7e7b56db42ceb8d2b8973eae678fa4b58d5d3659 Mon Sep 17 00:00:00 2001
From: Jesse Luehrs <doy@tozt.net>
Date: Wed, 13 May 2009 23:32:40 -0500
Subject: add old solutions

---
 2.lua | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 2.lua

(limited to '2.lua')

diff --git a/2.lua b/2.lua
new file mode 100644
index 0000000..d70cdc3
--- /dev/null
+++ b/2.lua
@@ -0,0 +1,30 @@
+local function memoize(fn)
+    local t = {}
+    return function(x)
+        local y = t[x]
+        if y == nil then y = fn(x); t[x] = y end
+        return y
+    end
+end
+
+fib = memoize(function(n)
+    if n < 3 then return 1 end
+    return fib(n - 1) + fib(n - 2)
+end)
+
+local root5 = math.sqrt(5)
+local phi = (1 + root5)/2
+local function fib2(n)
+    return math.floor((phi^n-(1-phi)^n)/root5+0.5)
+end
+
+local sum = 0
+local i = 0
+while true do
+    i = i + 1
+    local n = fib(i)
+    if n > 1000000 then break end
+    if n % 2 == 0 then sum = sum + n end
+end
+
+print(sum)
-- 
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