1 files changed, 130 insertions, 0 deletions

diff --git a/day16/__init__.py b/day16/__init__.py
new file mode 100644
index 0000000..66c0d36
--- /dev/null
+++ b/day16/__init__.py
@@ -0,0 +1,130 @@
+import math
+from abc import ABC
+from dataclasses import dataclass
+from typing import List, Tuple, Iterator, TypedDict, Dict, Union
+
+from aoc import BaseAssignment
+
+@dataclass
+class Packet:
+    raw: str
+    version: int = None
+    type: int = None
+    length_type = str
+    padding: int = 0
+    payload_length = None
+    payload_start = None
+    payload: Union[int, List['Packet']] = None
+
+    LITERAL = 4
+
+    FIFTEEN = '0'
+    ELEVEN = '1'
+
+    PAYLOAD_LENGTH_TYPE = {
+        FIFTEEN: 15,
+        ELEVEN: 11
+    }
+
+    @classmethod
+    def from_hex(cls, value: str) -> 'Packet':
+        print()
+        print(value)
+        for byte in value:
+            print(byte, bin(int(byte, 16))[2:].rjust(4, '0'))
+
+        bits = ''.join([
+            bin(int(byte, 16))[2:]
+                .rjust(4, '0')
+            for byte
+            in value
+        ])
+
+        return cls(
+            raw=bits
+        )
+
+
+    def __post_init__(self):
+        self.version = int(self.raw[:3], 2)
+        self.type = int(self.raw[3:6], 2)
+
+        match self.type:
+            case self.LITERAL:
+                self.payload = self.parse_literal()
+            case _:
+                self.length_type = self.raw[6]
+                self.payload_start = 8 + self.PAYLOAD_LENGTH_TYPE[self.length_type]
+                self.payload_length = int(self.raw[8:self.payload_start], 2)
+
+                print(self.raw[:3], self.raw[3:6], self.raw[7], self.raw[7:self.payload_start], self.raw[self.payload_start:])
+
+                self.payload = self.parse_operator()
+
+
+    def __len__(self):
+        return len(self.raw) - self.padding
+
+    def pad(self):
+        added_zeroes = 4 - len(self.raw) % 4
+        self.raw += added_zeroes * '0'
+        self.padding = added_zeroes
+
+    def parse_literal(self) -> int:
+        start_index = 6
+
+        end = False
+        bits = []
+
+        while not end:
+            bits.append(self.raw[start_index + 1:start_index + 5])
+            if self.raw[start_index] == '0':
+                end = True
+
+            start_index += 5
+
+        self.raw = self.raw[:start_index]
+        self.pad()
+
+        return int(''.join(bits), 2)
+
+    def parse_operator(self) -> List['Packet']:
+        packets = []
+        payload_end = self.payload_start + self.payload_length
+        payload = self.raw[self.payload_start:payload_end]
+
+        while len(payload) > 0:
+            packets.append(Packet(raw=payload))
+            payload = payload[len(packets[-1]):]
+
+        self.raw = self.raw[:payload_end]
+        self.pad()
+
+        return packets
+
+
+class Assignment(BaseAssignment, ABC):
+    def parse_item(self, item: str) -> Packet:
+        return Packet.from_hex(item)
+
+
+    def read_input(self, example=False) -> Packet:
+        return next(super().read_input(example))
+
+class AssignmentOne(Assignment):
+    example_result = 31
+
+    def version_sum(self, packet: Packet):
+        if packet.type == Packet.LITERAL:
+            return packet.version
+
+        return packet.version + sum(
+            self.version_sum(p)
+            for p in packet.payload
+        )
+
+    def run(self, input: Packet):
+        return self.version_sum(input)
+
+
+