aoc2022/03/rucksacks.py
2022-12-04 10:50:07 +01:00

46 lines
1.2 KiB
Python

import fileinput
from typing import Iterable
def letter_to_priority(i: str) -> int:
i = ord(i)
return (i & 0b11111) + (~((i & 0b00100000) >> 5) & 1) * 26
def compartment(items: str) -> int:
field = 0
for item in items:
field |= 1 << (letter_to_priority(item) - 1)
return field
def bitmap_to_priority(field: int) -> int:
for idx in range(52):
if field & 0b1:
return idx + 1
else:
field >>= 1
def solve(lines: Iterable[str]) -> int:
score = 0
for line in map(lambda x: x.strip(), lines):
items = len(line)
lh = compartment(line[:items//2])
rh = compartment(line[items//2:])
score += bitmap_to_priority(lh & rh)
return score
def solveb(lines: Iterable[str]) -> int:
score = 0
iterator = map(lambda x: x.strip(), lines.__iter__())
for first in iterator:
second = next(iterator)
third = next(iterator)
score += bitmap_to_priority(compartment(first) & compartment(second) & compartment(third))
return score
if __name__ == "__main__":
print(solve(fileinput.input()))
print(solveb(fileinput.input()))