Refactors files, adds asserts with the solutions

problem1.py

@@ -6,21 +6,21 @@
     233168
 """
 
-
 import itertools
-from utilities import lower_than
 
+from utilities import lower_than
 
-LIMIT=1000
-ANSWER=233168
+LIMIT = 1000
+ANSWER = 233168
 
 
 def multiples(n):
     """
     Yields all the multiples of n (to infinity)
     """
     for i in itertools.count(start=1):
-        yield i*n
+        yield i * n
+
 
 threes = itertools.takewhile(lower_than(LIMIT), multiples(3))
 fives = itertools.takewhile(lower_than(LIMIT), multiples(5))
@@ -31,4 +31,3 @@ def multiples(n):
 assert answer == ANSWER
 
 print answer
-

problem14.py

@@ -1,22 +1,26 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
-from utilities import lower_than
-from itertools import count, imap, takewhile
+from itertools import count, takewhile
 
-from functools import lru_cache
+from utilities import lower_than
 
 limit = 1e6
 
+cache = {1: 1}
+
 
-@lru_cache
 def collatz_len(n):
+    try:
+        return cache[n]
+    except KeyError:
+        retval = 1 + collatz_len((3 * n + 1) if (n % 2) else (n / 2))
+        cache[n] = retval
+        return retval
 
-    if n == 1:
-        return 1
-    else:
-        return 1 + collatz_len((3*n + 1) if (n % 2) else (n / 2))
 
+gen = ((n, collatz_len(n)) for n in takewhile(lower_than(limit), count(1)))
+answer = max(gen, key=lambda t: t[1])[0]
+assert answer == 837799
 
-answer = max(imap(collatz_len, takewhile(lower_than(limit), count(start=1))), key=lambda t: t[1])
-print(answer)
+print answer

problem2.py

@@ -1,9 +1,11 @@
 """
-Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be:
+Each new term in the Fibonacci sequence is generated by adding the previous two terms.
+By starting with 1 and 2, the first 10 terms will be:
 
 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...
 
-By considering the terms in the Fibonacci sequence whose values do not exceed four million, find the sum of the even-valued terms.
+By considering the terms in the Fibonacci sequence whose values do not exceed four million,
+find the sum of the even-valued terms.
 """
 
 import itertools
@@ -15,5 +17,5 @@
 seq = itertools.takewhile(lower_than(LIMIT), fibonacci())
 answer = sum(itertools.ifilter(lambda n: (n % 2) == 0, seq))
 
+assert answer == 4613732
 print answer
-

problem23.py

@@ -48,4 +48,7 @@ def is_sum_of_abundants(n):
 
 if __name__ == '__main__':
     numbers = xrange(upper_limit + 1)
-    print sum(n for n in numbers if not is_sum_of_abundants(n))
+    answer = sum(n for n in numbers if not is_sum_of_abundants(n))
+
+    assert answer == 4179871
+    print answer

problem25.py

@@ -8,7 +8,8 @@
 
 for i, f in enumerate(fibonacci()):
     if f >= M:
+        # The +1 is necessary because we index from 0, math starts from 1
+        answer = i + 1
+        assert answer == 4782
+        print answer
         break
-
-# The +1 is necessary because we index from 0, math starts from 1
-print i + 1

problem3.py

@@ -20,4 +20,5 @@
     if not number % p:
         answer = p
 
+assert answer == 6857
 print answer

problem30.py

@@ -37,4 +37,7 @@ def sum_fifth_powers(number):
             solutions.add(n)
 
     print solutions
-    print sum(solutions)
+    answer = sum(solutions)
+
+    assert answer == 443839
+    print answer

problem35.py

@@ -35,8 +35,11 @@ def is_circular_prime(n):
 
 
 if __name__ == '__main__':
+
     count = 0
     for n in xrange(2, int(1e6)):
         if is_circular_prime(n):
             count += 1
+
+    assert count == 55
     print count

problem41.py

@@ -41,5 +41,6 @@ def largest_pandigital_prime(n):
     for n in candidate_n:
         p = largest_pandigital_prime(n)
         if p:
+            assert p == 7652413
             print p
             break

problem7.py

@@ -2,11 +2,11 @@
 # -*- coding: utf-8 -*-
 
 import itertools
-from utilities import primes
 
+from utilities import primes
 
 N = int(1e4)
 answer = next(itertools.islice(primes(), N, N + 1))
 
+assert answer == 104743
 print answer
-

problem79.py

@@ -47,4 +47,5 @@ def remove_value(dictionary, value):
         remove_value(digits_preceding, first)
         solution += first
 
+    assert solution == '73162890'
     print solution

problem9.py

@@ -1,10 +1,10 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
-from utilities import lower_than
 import itertools
 import math
 
+from utilities import lower_than
 
 N = 1000
 
@@ -15,10 +15,9 @@ def is_perfect_square(n):
 
 
 def find_tuple():
-
-    for a in itertools.takewhile(lower_than(N-1), itertools.count(1)):
-        for b in itertools.takewhile(lower_than(N-a), itertools.count(a+1)):
-            c = math.sqrt(a*a + b*b)
+    for a in itertools.takewhile(lower_than(N - 1), itertools.count(1)):
+        for b in itertools.takewhile(lower_than(N - a), itertools.count(a + 1)):
+            c = math.sqrt(a * a + b * b)
             if a + b + c == N:
                 return a, b, int(c)
     else:
@@ -27,9 +26,10 @@ def find_tuple():
 
 a, b, c = find_tuple()
 
-assert a*a + b*b == c*c
+assert a * a + b * b == c * c
 assert a + b + c == N
 
 print a, b, c
-print a * b * c
 
+assert a * b * c == 31875000
+print a * b * c