42 lines
1.2 KiB
Python
42 lines
1.2 KiB
Python
#!/usr/bin/env python3
|
|
import fileinput
|
|
from copy import deepcopy
|
|
|
|
numbers = [[int(i) for i in line.strip()] for line in fileinput.input()]
|
|
bit_count = len(numbers[0])
|
|
|
|
occurrences = [0] * bit_count
|
|
for number in numbers:
|
|
for i, bit in enumerate(number):
|
|
occurrences[i] += bit
|
|
|
|
gamma, epsilon = 0, 0
|
|
for i, freq in enumerate(occurrences):
|
|
shifted = 1 << (len(occurrences) - 1) >> i
|
|
if freq > len(numbers) // 2:
|
|
gamma |= shifted
|
|
else:
|
|
epsilon |= shifted
|
|
|
|
print("part 1:", gamma * epsilon)
|
|
|
|
most_common = deepcopy(numbers)
|
|
least_common = deepcopy(numbers)
|
|
|
|
for i in range(bit_count):
|
|
ones = sum(number[i] for number in most_common)
|
|
lc = int(ones * 2 >= len(most_common))
|
|
most_common = [number for number in most_common if number[i] == lc]
|
|
if len(most_common) == 1:
|
|
break
|
|
|
|
for i in range(bit_count):
|
|
zeros = sum(not number[i] for number in least_common)
|
|
lc = int(zeros * 2 > len(least_common))
|
|
least_common = [number for number in least_common if number[i] == lc]
|
|
if len(least_common) == 1:
|
|
break
|
|
|
|
mc = int("".join(str(x) for x in most_common[0]), 2)
|
|
lc = int("".join(str(x) for x in least_common[0]), 2)
|
|
print("part 2:", mc * lc)
|