Exemple #1
0
# We shall say that an n-digit number is pandigital if it makes use of all the digits 1 to n exactly once. For example, 2143 is a 4-digit pandigital and is also prime.

# What is the largest n-digit pandigital prime that exists?

# Digit sum trick! number is divisible by 3 if and only if the digit sum of the number is divisible by 3
# simplifies problem to either  4 digit or 7 digit prime

# generate all primes beneath 7654321
# generate all possible 7 digit pandigital combinations

# largest 4 digit prime is 4231

from eulerhelpers import genprimes, isPandigital
from itertools import permutations

if __name__ == "__main__":
    primes = genprimes(7654321)
    x = 7654321

    while True:
        if isPandigital(x) and x in primes:
            print x
            break
        x -= 1

        if x <= 1000000:
            break
Exemple #2
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from eulerhelpers import isPandigital

#not as simple as saying 987654321 because n has to be greater than 1
#at n=2, it has to be 5 digit and 4 digit number
#seed must be 5000 or below

largest_pan = 123456789

for seed in range(9,10000):
	mult = 1 
	testpan = ''

	while len(testpan) < 9: 
		testpan += str(seed*mult)
		if len(testpan) >= 9: 
			if isPandigital(int(testpan)) and int(testpan) > largest_pan: 
				largest_pan = int(testpan)
		mult+=1

print "largest pandigital is", largest_pan