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AdventOfCode/2020/solutions/day_16.py
2020-12-25 23:50:29 +01:00

137 lines
4.2 KiB
Python

"""AOC 2020 Day 16"""
import pathlib
import time
import re
TEST_INPUT = """class: 1-3 or 5-7
row: 6-11 or 33-44
seat: 13-40 or 45-50
your ticket:
7,1,14
nearby tickets:
7,3,47
40,4,50
55,2,20
38,6,12"""
def read_input(input_path: str) -> str:
"""take input file path and return a str with the file's content"""
with open(input_path, 'r') as input_file:
input_data = input_file.read().strip()
return input_data
def extract(input_data: str) -> tuple:
"""take input data and return the appropriate data structure"""
values_rexp = re.compile(r'([0-9]+)-([0-9]+) or ([0-9]+)-([0-9]+)')
rules_str, ticket_str, nearby_tickets_str = input_data.split('\n\n')
rules = dict()
nearby_tickets = list()
for rule in rules_str.split('\n'):
field, vals = rule.split(': ')
ranges = values_rexp.match(vals)
rules[field] = (
(int(ranges.group(1)), int(ranges.group(2))),
(int(ranges.group(3)), int(ranges.group(4)))
)
my_ticket = list(map(int, ticket_str.split('\n')[1].split(',')))
for ticket in nearby_tickets_str.split('\n')[1:]:
nearby_tickets.append(list(map(int, ticket.split(','))))
return (rules, my_ticket, nearby_tickets)
def check_field(rule: tuple, field: int) -> bool:
"""check if a field is valid given a rule"""
for min_range, max_range in rule:
if min_range <= field <= max_range:
return True
return False
def find_invalid_field(rules: dict, ticket: list) -> int:
"""check if a ticket is valid or not"""
for field in ticket:
valid = False
for rule in rules.values():
valid = check_field(rule, field)
if valid:
break
if not valid:
return field
return None
def part1(entries: tuple) -> tuple:
"""part1 solver"""
rules, _, nearby_tickets = entries
valid_tickets = list()
invalid_fields_sum = 0
for ticket in nearby_tickets:
invalid_field = find_invalid_field(rules, ticket)
if invalid_field is not None:
invalid_fields_sum += invalid_field
else:
valid_tickets.append(ticket)
return valid_tickets, invalid_fields_sum
def part2(rules: dict, my_ticket: list, valid_tickets: list) -> int:
"""part2 solver"""
acceptable_fields = {key: [] for key in rules.keys()}
field_map = {key: None for key in rules.keys()}
departure_values_product = 1
for name, rule in rules.items():
for index in range(len(my_ticket)):
valid = True
for ticket in valid_tickets:
if not check_field(rule, ticket[index]):
valid = False
break
if valid:
acceptable_fields[name].append(index)
while not all(field is not None for field in field_map.values()):
removed_index = -1
for name, indexes in acceptable_fields.items():
if len(indexes) == 1:
field_map[name] = indexes[0]
removed_index = indexes[0]
break
for name, indexes in acceptable_fields.items():
if removed_index in indexes:
acceptable_fields[name].remove(removed_index)
for name, index in field_map.items():
if name.startswith('departure'):
departure_values_product *= my_ticket[index]
return departure_values_product
def test_input_day_16():
"""pytest testing function"""
entries = extract(TEST_INPUT)
_, invalid_fields_sum = part1(entries)
assert invalid_fields_sum == 71
def test_bench_day_16(benchmark):
"""pytest-benchmark function"""
benchmark(main)
def main():
"""main function"""
input_path = str(pathlib.Path(__file__).resolve().parent.parent) + "/inputs/" + str(pathlib.Path(__file__).stem)
start_time = time.time()
input_data = read_input(input_path)
entries = extract(input_data)
valid_tickets, invalid_fields_sum = part1(entries)
print("Part 1: %d" % invalid_fields_sum)
print("Part 2: %d" % part2(entries[0], entries[1], valid_tickets))
end_time = time.time()
print("Execution time: %f" % (end_time-start_time))
if __name__ == "__main__":
main()