5.md

Day 5

	Part 1	Part 2	Total
Time	14:44	1:57	16:41

Part 1

Pretty simple, just treating lists like stacks. I was slowed down by my bizarre decision to treat the front of a list as the top of the stack. .pop() defaults to getting the last element in a list...

import aocd
import re
with open("sess") as f:
    sess = f.readline()
din = aocd.get_data(session=sess, year=2022, day=5).split("\n")

size = 9
stacks = [[]] * size
stop = False

for line in din:
    if line.strip() == "":
        stop = True
        print(stacks)
        continue

    if not stop:
        a = 0
        for i in range(1, size * 4 + 1, 4):
            if line[i] != ' ' and line[i].isalpha():
                stacks[a] = stacks[a] + [line[i]]
            a += 1
    else:
        instr = list(map(int, re.findall(r'\d+', line)))
### SECTION TO BE MODIFIED FOR PART 2 ###
        for i in range(0, instr[0]):
            stacks[instr[2] - 1] = [stacks[instr[1] - 1].pop(0)] + stacks[instr[2] - 1]
### END SECTION ###
        print(stacks)

for thing in stacks:
    print(thing[0], end="")

Part 2

Very small modification to prepend the all of the pops in order rather than prepending them one by one. This line replaces all code in the section marked above.

stacks[instr[2] - 1] = [stacks[instr[1] - 1].pop(0) for i in range(0, instr[0])] + stacks[instr[2] - 1]