Project Euler #49

euler49.py

from math import sqrt
from itertools import takewhile, dropwhile, count

def comb(l):
    if len(l) == 0:
        yield []
    else:
        for i in range(len(l)):
            for cc in comb(l[:i] + l[i + 1:]):
                yield [l[i]] + cc
def combn(n):
    return [int(''.join(x)) for x in comb([c for c in str(n)])]

def isprime(n):
    for x in range(2, int(sqrt(n)) + 1):
        if n % x == 0:
            return 0
    return 1

def prime():
    primes = []
    for n in count(2):
        composite = 0
        for p in primes:
            if not n % p:
                composite = 1
                break
            elif p ** 2 > n:
                break
        if not composite:
            primes.append(n)
            yield n

print ''.join(str(s) for s in
            list([x, x + 3330, x + (3330 * 2)]
                for x in takewhile(lambda n: n < 10000,
                    (dropwhile(lambda n: n < 1000, prime())))
                        if isprime(x + 3330) and isprime(x + (3330 * 2))
                            and set([x + 3330, x + (3330 * 2)])
                                <= set(combn(x)))[1])