aoc_day5.py

import sys
from collections import defaultdict

infile = open("5.in")

inlines = [l for l in infile]
stacks = defaultdict(list)

def part1():
    boxparsing = True
    def take(move, from_, to_):
        f = stacks[int(from_)]
        t = stacks[int(to_)]
        for _ in range(int(move)):
            t.append(f.pop())

    for line in inlines:
        if boxparsing:
            for i in range(0, len(line), 4):
                if line[i] == "[":
                    stack = int(i / 4) + 1
                    stacks[stack].insert(0, line[i+1])

                if not line.strip():
                    boxparsing = False
        else:
            parts = line.split()
            _, count, _, from_, _, to_ = parts
            take(count, from_, to_)


    boxes = [stacks[i][-1] for i in sorted(stacks.keys())]
    print("part1", "".join(boxes))

def part2():
    boxparsing = True
    def take(move, from_, to_):
        f = stacks[int(from_)]
        t = stacks[int(to_)]
        tomove = []
        for _ in range(int(move)):
            tomove.append(f.pop())
        t.extend(reversed(tomove))

    for line in inlines:
        if boxparsing:
            for i in range(0, len(line), 4):
                if line[i] == "[":
                    stack = int(i / 4) + 1
                    stacks[stack].insert(0, line[i+1])

                if not line.strip():
                    boxparsing = False
        else:
            parts = line.split()
            _, count, _, from_, _, to_ = parts
            take(count, from_, to_)


    boxes = [stacks[i][-1] for i in sorted(stacks.keys())]
    print("part2", "".join(boxes))

part1()
part2()