6
⚙️ - 2023 DAY 19 SOLUTIONS -⚙️
(programming.dev)
Python
6.528 line-seconds (ranks 8th hardest after days 17, 8, 12, 16, 14, 11 and 10).
import functools
import operator
import re
import portion as P # noqa: N812
from .solver import Solver
def isize(i: P.Interval):
return sum(i_part.upper - i_part.lower - int(i_part.left == P.OPEN) + int(i_part.right == P.CLOSED)
for i_part in i)
class Day19(Solver):
workflows: dict[str, list[str|tuple[str, str, int, str]]]
parts: list[dict[str, int]]
def __init__(self):
super().__init__(19)
def presolve(self, input: str):
lines = input.splitlines()
self.workflows = {}
while lines:
line = lines.pop(0)
if not line:
break
name, program = line.split('{')
instructions = program[:-1].split(',')
self.workflows[name] = []
for item in instructions:
match_condition = re.fullmatch(r'(\w+)([<>])(\d+):(\w+)', item)
if match_condition:
category, op, threshold, goto = match_condition.groups()
self.workflows[name].append((category, op, int(threshold), goto))
else:
self.workflows[name].append(item)
self.parts = []
while lines:
items = lines.pop(0)[1:-1].split(',')
part = {}
for category, value in (i.split('=') for i in items):
part[category] = int(value)
self.parts.append(part)
def solve_first_star(self):
return sum(sum(part.values()) for part in self.parts if
self._count_options('in', 0, {c: P.singleton(v) for c, v in part.items()}) > 0)
def solve_second_star(self):
return self._count_options('in', 0, {c: P.closed(1, 4000) for c in self.parts[0].keys()})
def _count_options(self, workflow_name: str, workflow_index: int, ranges: dict[str, P.Interval]) -> int:
if workflow_name == 'A':
return functools.reduce(operator.mul, (isize(r) for r in ranges.values()), 1)
if workflow_name == 'R':
return 0
if any(isize(r) == 0 for r in ranges.values()):
return 0
match self.workflows[workflow_name][workflow_index]:
case (category, '>', threshold, goto):
new_ranges_true = {c: r & P.open(threshold, P.inf) if c == category else r for c, r in ranges.items()}
new_ranges_false = {c: r & P.openclosed(-P.inf, threshold) if c == category else r for c, r in ranges.items()}
return (self._count_options(goto, 0, new_ranges_true) +
self._count_options(workflow_name, workflow_index + 1, new_ranges_false))
case (category, '<', threshold, goto):
new_ranges_true = {c: r & P.open(-P.inf, threshold) if c == category else r for c, r in ranges.items()}
new_ranges_false = {c: r & P.closedopen(threshold, P.inf) if c == category else r for c, r in ranges.items()}
return (self._count_options(goto, 0, new_ranges_true) +
self._count_options(workflow_name, workflow_index + 1, new_ranges_false))
case next_workflow:
return self._count_options(next_workflow, 0, ranges)