advent-of-code/2021-python/solutions/day_03.py
Anders Ytterström 99f5385f25 Solve 2021:3 "Binary Diagnostic"
Yes, I do "".join(). Python is not always beautiful.

I began reusing part 1 for part 2, until I realised you cannot reuse the
Counter.most_common, and you need the actual values to be able to se
equal occourences.

I probably lost 5-15 minutes just to dribble with 3 levels of nested
objects. In GMT+1 before coffee, that cost me.

Part 2 was way uglier before some well motivated refactoring. Since all
tests and expected output were in place, refactoring was easy.
2021-12-03 07:29:34 +01:00

43 lines
1.2 KiB
Python

from collections import Counter
from solutions import BaseSolution
class Solution(BaseSolution):
input_file = "03.txt"
def __str__(self):
return "Day 3: Binary Diagnostic"
def parse_input(self, data):
return data.split()
def solve(self, puzzle_input):
e, g = self._eg(puzzle_input)
return int("".join(g), 2) * int("".join(e), 2)
def solve_again(self, puzzle_input):
og = self._ogco2(puzzle_input, "1")
co2 = self._ogco2(puzzle_input, "0")
return int("".join(og), 2) * int("".join(co2), 2)
def _eg(self, puzzle_input):
e = []
g = []
for r in zip(*puzzle_input):
x, y = Counter(r).most_common()
e.append(x[0])
g.append(y[0])
return e, g
def _ogco2(self, values, default, i=0):
eg = [Counter(r).most_common() for r in zip(*values)]
k = default if eg[i][0][1] == eg[i][1][1] else eg[i][abs(int(default) - 1)][0]
rem = [v for v in values if v[i] == k]
if len(rem) == 1:
return rem
return self._ogco2(rem, default, i + 1)
if __name__ == "__main__":
solution = Solution()
solution.show_results()