add 2020 day 16

README.md

@@ -3,7 +3,7 @@
 [![AoC 2017](https://img.shields.io/badge/2017-★_24-bcb01b)](https://adventofcode.com/2017)
 [![AoC 2018](https://img.shields.io/badge/2018-★_9-fb7938)](https://adventofcode.com/2018)
 [![AoC 2019](https://img.shields.io/badge/2019-★_6-f26e3c)](https://adventofcode.com/2019)
-[![AoC 2020](https://img.shields.io/badge/2020-★_2-e66241)](https://adventofcode.com/2020)
+[![AoC 2020](https://img.shields.io/badge/2020-★_4-ec683f)](https://adventofcode.com/2020)
 [![AoC 2021](https://img.shields.io/badge/2021-★_50-44cc11)](https://adventofcode.com/2021)
 [![AoC 2022](https://img.shields.io/badge/2022-★_50-44cc11)](https://adventofcode.com/2022)
 [![AoC 2023](https://img.shields.io/badge/2023-★_0-9f9f9f)](https://adventofcode.com/2023)

y2020/d16/__init__.py

@@ -0,0 +1,3 @@
+__year__ = 2020
+__day__ = 16
+__title__ = "Ticket Translation"

y2020/d16/cases/example.71..txt

@@ -0,0 +1,12 @@
+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

y2020/d16/solution.py

@@ -0,0 +1,85 @@
+import collections
+import functools
+
+from dataclasses import dataclass
+from math import prod
+
+from aoc.lib.sets import IntervalSet
+from aoc.lib.solution import SolutionBase
+
+import logging
+
+
+__all__ = ["Solution"]
+__log__ = logging.getLogger(__name__)
+
+Ticket = tuple[int, ...]
+
+
+@dataclass
+class Input:
+    rules: dict[str, IntervalSet]
+    own: Ticket
+    nearby: list[Ticket]
+
+
+class Solution(SolutionBase):
+    @staticmethod
+    def prepare(data):
+        return Input(
+            rules={
+                field: IntervalSet(
+                    *(
+                        map(int, interval.split("-"))
+                        for interval in value.strip().split(" or ")
+                    )
+                )
+                for field, value in (rule.split(":") for rule in data[0])
+            },
+            own=tuple(map(int, data[1][1].split(","))),
+            nearby=list(tuple(map(int, ticket.split(","))) for ticket in data[2][1:]),
+        )
+
+    @staticmethod
+    def part_01(data):
+        valid = functools.reduce(lambda a, b: a | b, data.rules.values())
+        return sum(sum(x for x in ticket if x not in valid) for ticket in data.nearby)
+
+    @staticmethod
+    def part_02(data):
+        valid = functools.reduce(lambda a, b: a | b, data.rules.values())
+        tickets = (ticket for ticket in data.nearby if all(x in valid for x in ticket))
+
+        investigate = collections.defaultdict(lambda: set(range(len(data.own) + 1)))
+        for ticket in tickets:
+            for name, values in data.rules.items():
+                investigate[name] &= {
+                    idx for idx, value in enumerate(ticket) if value in values
+                }
+
+        translate = {}
+        while investigate:
+            translate.update(
+                {
+                    code: opcodes.pop()
+                    for code, opcodes in investigate.items()
+                    if len(opcodes) == 1
+                }
+            )
+            investigate = {
+                code: opcodes - set(translate.values())
+                for code, opcodes in investigate.items()
+                if len(opcodes) > 1
+            }
+
+        return prod(
+            data.own[idx]
+            for name, idx in translate.items()
+            if name.startswith("departure")
+        )
+
+
+if __name__ == "__main__":
+    import aoc.lib.main
+
+    aoc.lib.main.main(Solution)