47 lines
979 B
Python
47 lines
979 B
Python
#!/usr/bin/env python3
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def primes(n):
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sieve = [True] * n
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for p in range(2, n):
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if not sieve[p]:
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continue
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for i in range(p**2, n, p):
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sieve[i] = False
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return [False]*2 + sieve[2:]
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sieve = primes(10**7)
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def is_prime(n):
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if n >= 10**7:
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return heuristic(n)
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return sieve[n]
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def heuristic(n):
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for i in range(2, int(n**0.5)+1): #slow and lazy
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if sieve[i] and n%i==0:
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return False
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return True
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def num(digs = set(range(1,10)), n=0, id=[]):
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c = 0
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for d in [i for i in digs if i>n]:
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c += dig(digs-{d}, d, d, id)
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return c
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def dig(digs, n, p, id):
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c = check(p, digs, n, id)
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for d in digs:
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c += dig(digs-{d}, n, 10*p + d, id)
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return c
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def check(p, digs, n, id):
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if len(digs) > 0 and max(digs) < n:
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return 0
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if not is_prime(p):
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return 0
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if len(digs) == 0:
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return 1
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return num(digs, n, id)
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print(num())
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