Strictly speaking this algorithm has an O(n^2) part in it, but it runs under a second so...
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46
51/main.py
46
51/main.py
@@ -8,6 +8,7 @@ Find the smallest prime which, by replacing part of the number (not necessarily
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import numpy as np
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import math
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import time
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def sieve(n):
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assert n > 1
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@@ -24,13 +25,52 @@ def sieve(n):
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return [i for i,val in enumerate(ns) if val][2:]
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# Does generate all families that can be made for that number, so that consists of multiple families together
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def families(num):
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result = []
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variedDigits = set()
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digits = [int(d) for d in str(num)]
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for i in range(len(digits)):
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if not i in variedDigits:
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buddies = []
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for j in range(len(digits)):
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if digits[i] == digits[j]:
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buddies.append(j)
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variedDigits.add(j)
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r = digits[:]
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for n in range(10):
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for bud in buddies:
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r[bud] = n
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maybeResult = int("".join([str(_r) for _r in r]))
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result.append(maybeResult)
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return result
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def findPrimeFamily(length):
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primes = sieve(1000000)
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primeSet = set(primes)
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for p in primes:
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primeFamilies = families(p)
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for i in range(len(primeFamilies) // 10):
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counter = 0
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for pf in primeFamilies[10*i:10*i+10]:
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if pf in primeSet and len(str(pf)) == len(str(p)):
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counter += 1
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if counter >= length:
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return [x for x in primeFamilies[10*i:10*i+10] if x in primeSet]
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def main():
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print("Hello this is Patrick")
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primes = sieve(1000000)
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t0 = time.time()
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# So instead of going past all number families and see if they are prime I think it's better to look for families in the primes
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# Quite the combinatorial problem indeed, lots of permutations and I don't immediately see an easy way to fix it
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print(findPrimeFamily(8), time.time() - t0)
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if __name__ == "__main__":
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main()
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