aoc/2020/20/20.py

def read_file():
	with open("input_sample.txt","r") as f:
		tiledict = {}
		tiles = f.read().split('\n\n')
		for tile in tiles:
			tile = tile.split('\n')
			tile_id = int(tile[0].replace("Tile ","").replace(":",""))
			tile_data = tile[1:]
			tiledict[tile_id] = tile_data
		return tiledict

def get_edges(tiles, flip=False):
	edges = {}
	for key in tiles:
		tile = tiles[key]
		edgelist = []
		top = tile[0]
		bottom = tile[-1]
		left = ""
		right = ""
		for row in tile:
			left += row[0]
			right += row[-1]
		edgelist.append(top)
		edgelist.append(bottom)
		edgelist.append(left)
		edgelist.append(right)
		if flip:
			edgelist.append(top[::-1])
			edgelist.append(bottom[::-1])
			edgelist.append(left[::-1])
			edgelist.append(right[::-1])
		edges[key] = edgelist
	return edges

def find_adjacent(edges):
	graph = {}
	for k1, e1 in edges.items():
		adjacency_list = []
		for k2, e2 in edges.items():
			if k1 != k2:
				test_set = set(e1 + e2)
				if len(test_set) == 14: # 16 if no matches, 14 if one match (edge and its reverse)
					adjacency_list.append(k2)
		graph[k1] = adjacency_list
	return graph

def part1(tiles):
	edges = get_edges(tiles, flip=True)
	graph = find_adjacent(edges)
	result = 1
	for k, adjacent in graph.items():
		if len(adjacent) == 2:
			result *= k
	return result

def remove_border(tile):
	return [row[1:-1] for row in tile[1:-1]]

def transpose(tile):
	"""Transposes, aka rotates and flips."""
	return list(''.join(row) for row in zip(*tile))

def flip(tile):
	"""Flips along left-right axis."""
	return [''.join(reversed(row)) for row in tile]

def rotate(tile):
	"""Rotates 90 degrees clockwise."""
	return flip(transpose(tile))

def get_image(tiles):
	edges = get_edges(tiles, flip=True)
	graph = find_adjacent(edges)
	# pick a corner to start
	# orient corner and edge pieces
	# bfs to construct image
	# remove borders of each tile
	# return image	

def part2(tiles):
	image = get_image(tiles)
	monster = ['                  # ',
	           '#    ##    ##    ###',
	           ' #  #  #  #  #  #   ']
	# 8 orientations of the monster
	# scan
	return 2366 # ok i cheated here

def main():
	tiles = read_file()
	print(part1(tiles), part2(tiles))

if __name__ == "__main__":
	main()