45 lines
1.2 KiB
Python
45 lines
1.2 KiB
Python
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def repeat(n, xs):
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return [xs for _ in range(n)]
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def sequence(xss, acc):
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if not xss:
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return acc
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return sequence(xss[1:], [a + [x] for x in xss[0] for a in acc])
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def is_balanced(xs):
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""" Check if subsets are balanced. That means for every lower number there
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is a higher number that balances it out. """
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ones_balanced, twos_balanced = True, True
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ones, twos = 0, 0
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for x in xs:
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if x == 1:
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ones += 1
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twos -= 1
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elif x == 2:
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ones -= 1
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twos += 1
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if ones < 0:
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ones_balanced = False
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if twos < 0:
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twos_balanced = False
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return ones_balanced or twos_balanced
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def euler_106():
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n = 12
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# Generate all possible subsets where both subsets have the same number of
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# elements and at least two elements per subset.
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xs = repeat(n, [0, 1, 2])
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xs = [x for x in sequence(xs, [[]])
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if x.count(1) > 1
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if x.count(1) == x.count(2)]
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return len([1 for x in xs if not is_balanced(x)]) // 2
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if __name__ == "__main__":
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solution = euler_106()
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print("e106.py: " + str(solution))
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assert(solution == 21384)
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