Added solution for Problem #16

Moved common functions from solutions 4 and 16 into lib/digits.py, which
has a function that returns a list containing the digits of an input number.

004/4.py

@@ -1,24 +1,23 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
+import sys, math
+sys.path.append('../lib')
+from digits import get_digits
+
 """
 I’m trying a very brute force approach here. There probably is a way to this
 algebraically, not numerically.
 """
-    
+
 def is_palindrome(number):
     """ Return true if the number is a palindrome.
     
     Start dividing the number by 10, 100, 1000, etc to get the digits
     from the right-hand side of the number.
     """
-    digits = []
-    divisor = 10.0
-    while number * 10 / divisor > 0.1:
-        remainder = number % divisor
-        digits.append(remainder / (divisor / 10)) # Find the first digit of this number
-        number = number - remainder # Round-up the number so that there is no extra remainder
-        divisor = divisor * 10 # increase the divisor to get the next number
+
+    digits = get_digits(number)
 
     palindrome = True
     for (k, v) in zip(digits, reversed(digits)):

016/16.py

@@ -0,0 +1,8 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+import sys
+sys.path.append('../lib')
+from digits import get_digits
+
+print sum(reversed(get_digits(2 ** 1000)))

016/README.py

@@ -0,0 +1,6 @@
+# Problem 16
+
+2^(15) = 32768 and the sum of its digits is 3 + 2 + 7 + 6 + 8 = 26.
+
+What is the sum of the digits of the number 2^(1000)?
+

lib/digits.py

@@ -0,0 +1,14 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+def get_digits(number):
+    """ Return the digits present in the number """
+    digits = []
+    divisor = 10
+    while number * 10.0 / divisor > 0.1:
+        remainder = number % divisor
+        digits.append(int(remainder / (divisor / 10))) # Find the first digit of this number
+        number = number - remainder # Round-up the number so that there is no extra remainder
+        divisor = divisor * 10 # increase the divisor to get the next number
+
+    return digits