Moved 20 to 26 to Python.

python/e026.py

@@ -1,38 +1,31 @@
-def primes(n):
-    """ Nice way to calculate primes.  Should be fast. """
-    l = range(2, n + 1)
-    _l = []
-    while True:
-        p = l[0]
-        if p * p > n:
-            return _l + l
-        l = [i for i in l if i % p != 0]
-        _l.append(p)
+from itertools import count
 
 
-def produce_prime(a, b, n, primes):
-    x = n*n + a*n + b
-    return x in primes
-    
+def get_cycle_count(nominator, denominator):
+    assert(nominator == 1)
+    remainders = {}
+    remainder = nominator
+    results = []
+    for i in count():
+        result = remainder // denominator
+        remainder = remainder % denominator
+        results.append(result)
+        if remainder in remainders:
+            return i - remainders[remainder]
+        else:
+            remainders[remainder] = i
+        if remainder == 0:
+            return 0
+        remainder *= 10
 
 
-def f_027():
-    """ n^2 + a*n + b
-        1) b must be prime
-    """
-    p6 = set(primes(1000000))
-    p3 = primes(1000)
-    options = [(a, b)
-               for a in range(1, 1000, 2)
-               for b in p3]
-
-    print(len(options))
-    for n in range(100):
-        options = [(a, b)
-                   for a, b in options
-                   if produce_prime(a, b, n, p6)]
-        print(options)
-    print(len(options))
+def euler_026():
+    return max([(get_cycle_count(1, i), i) for i in range(1, 1000)])[1]
 
 
-f_027()
+if __name__ == "__main__":
+    assert(get_cycle_count(1, 7) == 6)
+    assert(get_cycle_count(1, 10) == 0)
+    assert(get_cycle_count(1, 6) == 1)
+    print("e026.py: {}".format(euler_026()))
+    assert(euler_026() == 983)