advent-of-code/2022/d05/ex1/ex1.py

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2022-12-05 08:26:01 +01:00
#!/usr/bin/env python
import dataclasses
import sys
Stack = list[str]
@dataclasses.dataclass
class Instruction:
n: int
start: int
end: int
@classmethod
def from_input(cls, input: str) -> "Instruction":
words = input.split()
return Instruction(int(words[1]), int(words[3]) - 1, int(words[5]) - 1)
def parse(input: list[str]) -> tuple[list[Stack], list[Instruction]]:
def parse_stacks(input: list[str]) -> list[Stack]:
stacks: list[Stack] = [[] for _ in range(1, len(input[-1]), 4)]
for line in reversed(input[:-1]):
for stack, i in enumerate(range(1, len(line), 4)):
c = line[i]
if c == " ":
continue
stacks[stack].append(c)
return stacks
def parse_instructions(input: list[str]) -> list[Instruction]:
return list(map(Instruction.from_input, input))
empty_line = input.index("")
return parse_stacks(input[:empty_line]), parse_instructions(input[empty_line + 1 :])
def solve(input: list[str]) -> str:
stacks, instructions = parse(input)
for instr in instructions:
start, end = stacks[instr.start], stacks[instr.end]
items = (start.pop() for _ in range(instr.n))
end.extend(items)
return "".join(stack[-1] for stack in stacks if stack)
def main() -> None:
input = sys.stdin.read().splitlines()
print(solve(input))
if __name__ == "__main__":
main()