Moved some common functions to 'utils'

frac.py

-def _gcd(a, b):
-    while b:
-        a, b = b, a % b
-
-    return a
-
-def gcd(*args):
-    return reduce(_gcd, args)

problem243.py

 #!/usr/bin/env python
 from __future__ import division
-from primes import is_prime, nprimes
+from utils import is_prime, nprimes
 
 print list(nprimes(15499))
 import sys; sys.exit()

problem33.py

 #!/usr/bin/env python
 from __future__ import division
 from itertools import combinations, permutations
-from frac import gcd
+from utils import gcd
 
 nrs = [(i, str(i)) for i in xrange(10, 100)]
 pairs = ((0, 0), (0, 1), (1, 0), (1, 1))

problem41.py

 #!/usr/bin/env python
-def is_prime(n):
-    if n == 2:
-        return True
+from utils import is_prime
 
-    if n < 2 or not n & 1:
-        return False
+from itertools import permutations
 
-    for i in xrange(3, int(n ** .5) + 1, 2):
-        if not divmod(n, i)[1]:
-            return False
+m = 0
 
-    return True
-
-if __name__ == '__main__':
-    from itertools import permutations
-
-    m = 0
-
-    for i in xrange(2, 10):
+for i in xrange(2, 10):
     for digits in permutations(map(str, range(i, 0, -1))):
         n = int(''.join(digits))
 
         if n > m and is_prime(n):
             m = n
 
-    print m
+print m

primes.py → utils.py

+def _gcd(a, b):
+    while b:
+        a, b = b, a % b
+
+    return a
+
+def gcd(*args):
+    return reduce(_gcd, args)
+
 def is_prime(n):
     if n == 2:
         return True