23.md

Day 23

	Part 1	Part 2	Total
Time	>24h	2:17	>24h

This is another day that I didn't stay up until midnight to do the problem when it came out. Completed on 12/24. Took roughly 55:19 in total.

Part 1

from helpers.datagetter import data_in, submit
from collections import defaultdict

ans = 0
din = data_in(split=True, numbers=False)
grid = defaultdict(int)

for i in range(len(din)):
    for j in range(len(din[0])):
        if din[i][j] == "#":
            grid[(j, i)] = 1

num_elves = len(grid)


def get_adjacent(at):
    x, y = at
    output = []
    for i in range(-1, 2):
        output.append(grid[(x + i, y - 1)])
    output.append(grid[(x + 1, y)])
    for i in range(1, -2, -1):
        output.append(grid[(x + i, y + 1)])
    output.append(grid[(x - 1, y)])
    output.append(grid[(x - 1, y - 1)])
    return output


dire = 0

# Simulate 10 rounds
for _ in range(10):
    elves = grid.copy().keys()
    moves = defaultdict(list)

    for elf in elves:
        if grid[elf] != 1:
            continue

        adj = get_adjacent(elf)
        if max(adj) == 0:
            continue

        for i in range(4):
            if (dire + i) % 4 == 0:
                if max(adj[0:3]) == 0:
                    moves[(elf[0], elf[1] - 1)].append(elf)
                    break
            elif (dire + i) % 4 == 1:
                if max(adj[4:7]) == 0:
                    moves[(elf[0], elf[1] + 1)].append(elf)
                    break
            elif (dire + i) % 4 == 2:
                if max(adj[6:9]) == 0:
                    moves[(elf[0] - 1, elf[1])].append(elf)
                    break
            elif (dire + i) % 4 == 3:
                if max(adj[2:5]) == 0:
                    moves[(elf[0] + 1, elf[1])].append(elf)
                    break

    for to, elves in moves.items():
        if len(elves) == 1:
            grid[elves[0]] = 0
            grid[to] = 1

    dire += 1


tl = [5, 5]
br = [5, 5]
for key, val in grid.items():
    if val:
        tl[0] = min(tl[0], key[0])
        br[0] = max(br[0], key[0])
        tl[1] = min(tl[1], key[1])
        br[1] = max(br[1], key[1])

ans = (br[1] - tl[1] + 1) * (br[0] - tl[0] + 1) - num_elves
print(ans)
submit(ans)

Part 2

Small change to make it run until all elves don't have any other elves around them.

from helpers.datagetter import data_in, submit
from collections import defaultdict

ans = 0
din = data_in(split=True, numbers=False)
grid = defaultdict(int)

for i in range(len(din)):
    for j in range(len(din[0])):
        if din[i][j] == "#":
            grid[(j, i)] = 1

num_elves = len(grid)


def get_adjacent(at):
    x, y = at
    output = []
    for i in range(-1, 2):
        output.append(grid[(x + i, y - 1)])
    output.append(grid[(x + 1, y)])
    for i in range(1, -2, -1):
        output.append(grid[(x + i, y + 1)])
    output.append(grid[(x - 1, y)])
    output.append(grid[(x - 1, y - 1)])
    return output


dire = 0
found = True

while found:
    elves = grid.copy().keys()
    moves = defaultdict(list)
    found = False

    for elf in elves:
        if grid[elf] != 1:
            continue

        adj = get_adjacent(elf)
        if max(adj) == 0:
            continue
        found = True

        for i in range(4):
            if (dire + i) % 4 == 0:
                if max(adj[0:3]) == 0:
                    moves[(elf[0], elf[1] - 1)].append(elf)
                    break
            elif (dire + i) % 4 == 1:
                if max(adj[4:7]) == 0:
                    moves[(elf[0], elf[1] + 1)].append(elf)
                    break
            elif (dire + i) % 4 == 2:
                if max(adj[6:9]) == 0:
                    moves[(elf[0] - 1, elf[1])].append(elf)
                    break
            elif (dire + i) % 4 == 3:
                if max(adj[2:5]) == 0:
                    moves[(elf[0] + 1, elf[1])].append(elf)
                    break

    for to, elves in moves.items():
        if len(elves) == 1:
            grid[elves[0]] = 0
            grid[to] = 1

    dire += 1

print(dire)
submit(dire)