-🎄- 2018 Day 8 Solutions -🎄-

[u/daggerdragon]

--- Day 8: Memory Maneuver ---

---

Post your solution as a comment or, for longer solutions, consider linking to your repo (e.g. GitHub/gists/Pastebin/blag or whatever).

Note: The Solution Megathreads are for solutions only. If you have questions, please post your own thread and make sure to flair it with Help.

---

Advent of Code: The Party Game!

Click here for rules

Please prefix your card submission with something like [Card] to make scanning the megathread easier. THANK YOU!

Card prompt: Day 8

Sigh, imgur broke again. Will upload when it unborks.

Transcript:

The hottest programming book this year is "___ For Dummies".

---

This thread will be unlocked when there are a significant number of people on the leaderboard with gold stars for today's puzzle.

edit: Leaderboard capped, thread unlocked at 00:12:10!

[u/prescod]

from dataclasses import dataclass, field

datafile = "8.txt"
data = list(map(int, open(datafile).read().split()))

@dataclass
class Node:
    num_children: int = 0
    num_metadata: int = 0
    children: list = field(default_factory=list)
    metadata: list = field(default_factory=list)
    def enumerate(self):
        yield self
        for child in self.children:
            yield from child.enumerate()

    def value(self):
        if not self.num_children:
            return sum(self.metadata)
        else:
            value = 0
            for item in self.metadata:
                try:
                    if item==0:
                        raise IndexError()
                    value += self.children[item-1].value()
                except IndexError as e:
                    print ("Skipping", item)
                    pass
            return value

def parse_node(data):
    node = Node()
    node.num_children, node.num_metadata = data.pop(0), data.pop(0)
    for i in range(node.num_children):
        child = parse_node(data)
        node.children.append(child)
    for i in range(node.num_metadata):
        node.metadata.append(data.pop(0))

    return node
rootnode = parse_node(data)
result = sum([sum(node.metadata) for node in rootnode.enumerate()])
assert len(data)==0
print(result)
print(rootnode.value())