def main():
cube = Cube(read_full_text(2020, 17), 4)
for _ in range(6):
cube.simulate_cycle()
print(cube.count_active())
def main():
text = read_full_text(2020, 19)
[rules, messages] = text.split("\n\n")
rules = rules.splitlines()
# Need to slightly change formatting so precedence rules work.
# Space cannot be both an operator and space - it just doesn't make sense,
# so remove spaces around |, which are just for display.
rules = {
int(index): rule.replace(" | ", "|").strip()
for [index, rule] in [rule.split(":") for rule in rules]
}
messages = messages.splitlines()
lexer = RuleLexer()
parser = RuleParser()
for rule in rules:
rules[rule] = parser.parse(lexer.tokenize(rules[rule]))
regex = re.compile("^" + generate_regex(rules, 0) + "$")
count = 0
for message in messages:
if regex.match(message):
count += 1
print(count)
def main():
text = read_full_text(2020, 16)
fields = get_fields(text)
nearby_tickets = get_tickets("nearby", text)
your_ticket = get_tickets("your", text)[0]
invalid_values = []
all_fields = set(chain.from_iterable(fields.values()))
valid_tickets = []
for ticket in nearby_tickets:
if all([value in all_fields for value in ticket]):
valid_tickets.append(ticket)
# List of each column of the CSV.
column_values = list(zip(*valid_tickets))
# Dictionary of field name to potential indices.
field_indices = {
field: set(range(len(valid_tickets[0])))
for field in fields.keys()
}
# Remove column numbers for each field that does not match the ranges.
for i in range(len(column_values)):
for field, range_ in fields.items():
values_in_range = [
value for value in column_values[i] if value in range_
]
if len(values_in_range) != len(column_values[i]):
field_indices[field].remove(i)
# Whiddle down indices by setting an int for any field that has only one possible index,
# then remove that index from all other fields, since it can only be used once.
#
# Repeat until all fields have been resolved.
while True:
for field, values in field_indices.items():
if isinstance(values, set) and len(values) == 1:
field_indices[field] = list(values)[0]
for values_ in field_indices.values():
if isinstance(values_,
set) and field_indices[field] in values_:
values_.remove(field_indices[field])
if all(isinstance(_values, int) for _values in field_indices.values()):
break
print(
reduce(
mul,
[
your_ticket[index] for field, index in field_indices.items()
if field.startswith("departure")
],
))
def main():
text = read_full_text(2020, 19)
[rules, messages] = text.split("\n\n")
rules = rules.splitlines()
# Need to slightly change formatting so precedence rules work.
# Space cannot be both an operator and space - it just doesn't make sense,
# so remove spaces around |, which are just for display.
rules = {
int(index): rule.replace(" | ", "|").strip()
for [index, rule] in [rule.split(":") for rule in rules]
}
messages = messages.splitlines()
lexer = RuleLexer()
parser = RuleParser()
for rule in rules:
rules[rule] = parser.parse(lexer.tokenize(rules[rule]))
rule_res = {}
for rule in sorted(rules.keys()):
if rule == 0 or rule == 8 or rule == 11:
continue
rule_res[rule] = generate_regex(rules, rule)
# Pattern 8 is just pattern 42 one or more times
rule_res[8] = f"(?:{rule_res[42]}+)"
# Pattern 11 needs to specifically use a recursive regex
rule_res[
11] = f"(?:({rule_res[42]}{rule_res[31]}|{rule_res[42]}(?-1){rule_res[31]}))"
# Now that we have patterns 8 and 11 we can build pattern 0
rule_res[0] = f"^(?:{rule_res[8]}{rule_res[11]})$"
count = 0
for message in messages:
# Need to use perl because Python does not have recursive regex
# (could use the regex module but don't feel like it)
proc = subprocess.run(
f"perl -e 'print \"{message}\" =~ /{rule_res[0]}/ ? 1 : 0'",
capture_output=True,
shell=True,
)
if int(proc.stdout) == 1:
count += 1
print(count)
def main():
text = read_full_text(2020, 16)
fields = get_fields(text)
nearby_tickets = get_tickets("nearby", text)
your_tickets = get_tickets("your", text)
invalid_values = []
all_values = list(chain.from_iterable(nearby_tickets))
all_fields = set(chain.from_iterable(chain.from_iterable(fields.values())))
for value in all_values:
if value not in all_fields:
invalid_values.append(value)
print(sum(invalid_values))
def main():
text = read_full_text(2020, 20)
tiles = {
int(id_): Tile(tile)
for id_, tile in re.findall(r"Tile (\d+):\n([\.#\n]+)", text)
}
matches = defaultdict(lambda: 0)
for tile_a, tile_b in product(tiles, tiles):
if tile_a == tile_b:
continue
matches[tile_a] += len(tiles[tile_a].match_tile(tiles[tile_b]))
print(reduce(mul, (id_ for id_, matches in matches.items() if matches == 2)))
def main():
text = read_full_text(2020, 20)
tiles = {
int(id_): Tile(tile)
for id_, tile in re.findall(r"Tile (\d+):\n([\.#\n]+)", text)
}
matches = defaultdict(lambda: 0)
for tile_a, tile_b in product(tiles, tiles):
if tile_a == tile_b:
continue
matches[tile_a] += len(tiles[tile_a].match_tile(tiles[tile_b]))
corners = [tiles[id_] for id_, matches in matches.items() if matches == 2]
corners[0].extend_corner(tiles.values())
def get_passenger_groups():
return (group.strip().split("\n")
for group in read_full_text(2020, 6).split("\n\n"))
def get_passport_chunks() -> Iterator[str]:
"""Read the input text into individual passport chunks."""
text = read_full_text(2020, 4)
return (re.sub(r"\s+", " ", chunk) for chunk in text.split("\n\n"))