Solution to problem 16 in Python (failed mypy :()

src/P16.py

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+# --- Day 16: Ticket Translation ---
+
+# As you're walking to yet another connecting flight, you realize that one of
+# the legs of your re-routed trip coming up is on a high-speed train. However,
+# the train ticket you were given is in a language you don't understand. You
+# should probably figure out what it says before you get to the train station
+# after the next flight.
+
+# Unfortunately, you can't actually read the words on the ticket. You can,
+# however, read the numbers, and so you figure out the fields these tickets
+# must have and the valid ranges for values in those fields.
+
+# You collect the rules for ticket fields, the numbers on your ticket, and the
+# numbers on other nearby tickets for the same train service (via the airport
+# security cameras) together into a single document you can reference (your
+# puzzle input).
+
+# The rules for ticket fields specify a list of fields that exist somewhere on
+# the ticket and the valid ranges of values for each field. For example, a rule
+# like class: 1-3 or 5-7 means that one of the fields in every ticket is named
+# class and can be any value in the ranges 1-3 or 5-7 (inclusive, such that 3
+# and 5 are both valid in this field, but 4 is not).
+
+# Each ticket is represented by a single line of comma-separated values. The
+# values are the numbers on the ticket in the order they appear; every ticket
+# has the same format. For example, consider this ticket:
+
+# .--------------------------------------------------------.
+# | ????: 101    ?????: 102   ??????????: 103     ???: 104 |
+# |                                                        |
+# | ??: 301  ??: 302             ???????: 303      ??????? |
+# | ??: 401  ??: 402           ???? ????: 403    ????????? |
+# '--------------------------------------------------------'
+
+# Here, ? represents text in a language you don't understand. This ticket might
+# be represented as 101,102,103,104,301,302,303,401,402,403; of course, the
+# actual train tickets you're looking at are much more complicated. In any
+# case, you've extracted just the numbers in such a way that the first number
+# is always the same specific field, the second number is always a different
+# specific field, and so on - you just don't know what each position actually
+# means!
+
+# Start by determining which tickets are completely invalid; these are tickets
+# that contain values which aren't valid for any field. Ignore your ticket for
+# now.
+
+# For example, suppose you have the following notes:
+
+# class: 1-3 or 5-7
+# row: 6-11 or 33-44
+# seat: 13-40 or 45-46
+
+# your ticket:
+# 7,1,14
+
+# nearby tickets:
+# 7,3,47
+# 40,4,50
+# 55,2,20
+# 38,6,12
+
+# It doesn't matter which position corresponds to which field; you can identify
+# invalid nearby tickets by considering only whether tickets contain values
+# that are not valid for any field. In this example, the values on the first
+# nearby ticket are all valid for at least one field. This is not true of the
+# other three nearby tickets: the values 4, 55, and 12 are are not valid for
+# any field. Adding together all of the invalid values produces your ticket
+# scanning error rate: 4 + 55 + 12 = 71.
+
+# Consider the validity of the nearby tickets you scanned. What is your ticket
+# scanning error rate?
+
+from typing import Set
+
+with open("files/P16.txt", "r") as f:
+    rules_raw, my_ticket, nearby_tickets = [
+        f.split("\n") for f in f.read().strip().split("\n\n")
+    ]
+
+
+def part_1() -> None:
+    rules = []
+    for rule in rules_raw:
+        name = rule.split(": ")[0]
+        valid_numbers = set()
+        for range_numbers in rule.split(": ")[1].split(" or "):
+            numbers = [int(number) for number in range_numbers.split("-")]
+            first, last = range(*numbers).start, range(*numbers).stop
+            list_numbers = list(range(first, last + 1))
+            for number in list_numbers:
+                valid_numbers.add(number)
+        rules.append([name, valid_numbers])
+
+    # Create a single set with all rules
+    all_rules: Set[int] = set()
+    for rule in rules:
+        all_rules |= rule[1]
+
+    all_tickets = [list(map(int, o.split(","))) for o in nearby_tickets[1:]]
+
+    ticket_scanning_error_rate = sum(
+        [
+            ticket
+            for ticket_numbers in all_tickets
+            for ticket in ticket_numbers
+            if ticket not in all_rules
+        ]
+    )
+
+    print(f"The ticket scanning error rate is {ticket_scanning_error_rate}")
+
+
+if __name__ == "__main__":
+    part_1()