56 lines
1.3 KiB
Python
56 lines
1.3 KiB
Python
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VERBOSE = False
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def get_input(sample = False, part = 1):
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global n_bits
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with open(f'sample_p{part}' if sample else 'input', 'r') as f:
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tmp = f.readlines()
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n_bits = len(tmp[0]) - 1
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return [int(line.strip(), 2) for line in tmp]
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def verbose(s):
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if VERBOSE:
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print(s)
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def filter_by(most, inp):
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global n_bits
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for i in range(n_bits - 1, -1, -1):
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dic = {0: [], 1: []}
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for n in inp:
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dic[(n >> i) & 1].append(n)
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verbose(dic)
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if len(dic[1]) >= len(dic[0]):
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inp = dic[1 if most else 0][:]
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else:
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inp = dic[0 if most else 1][:]
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if len(inp) == 1:
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return inp[0]
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def result(inp, part = 1):
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global n_bits
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if part == 1:
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# print(n_bits)
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tot = len(inp)
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gamma = eps = 0
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for i in range(n_bits):
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ones = 0
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for n in inp:
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ones += (n >> i) & 1
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a = 1 if ones > tot/2 else 0
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gamma |= a << i
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eps = (2**n_bits - 1) ^ gamma
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return eps * gamma
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else:
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ox = filter_by(True, inp)
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co = filter_by(False, inp)
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verbose(f"{ox = }, {co = }")
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return ox * co
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if __name__ == "__main__":
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print(result(get_input(), part = 2))
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