advent-of-code/2025/d01/ex2/ex2.py
2025-12-01 12:02:58 +00:00

40 lines
948 B
Python
Executable file

#!/usr/bin/env python
import itertools
import sys
def sign(n: int) -> int:
if n == 0:
return 0
return n // abs(n)
def solve(input: list[str]) -> int:
def parse_turn(input: str) -> int:
direction = input[0]
clicks = int(input[1:])
return clicks * (1 if direction == "R" else -1)
def parse(input: list[str]) -> list[int]:
return [parse_turn(turn) for turn in input]
def count_zeros(before: int, after: int) -> int:
delta = after - before
to_zero = (before % 100) * -sign(delta)
if to_zero <= 0:
to_zero += 100
return (abs(delta) + 100 - to_zero) // 100
turns = parse(input)
positions = itertools.accumulate(turns, initial=50)
return sum(count_zeros(a, b) for a, b in itertools.pairwise(positions))
def main() -> None:
input = sys.stdin.read().splitlines()
print(solve(input))
if __name__ == "__main__":
main()