aoc2020/day11.py
2020-12-11 12:35:36 +01:00

90 lines
2.7 KiB
Python

from collections import defaultdict
import aoclib
DAY = 11
TEST_SOLUTION_PART1 = 37
TEST_SOLUTION_PART2 = 26
INT_INDEX = ['L', '#', '.']
MAP_INDEX = [False, True, None]
def printLayout(layout, max_x, max_y):
for y in range(0, max_y):
for x in range(0, max_x):
print(INT_INDEX[layout[(x, y)]], end="")
print()
def prepareLayout(raw_input):
int_layout = defaultdict(lambda: None)
for y, line in enumerate(raw_input):
for x, char in enumerate(line):
int_layout[(x, y)] = MAP_INDEX[INT_INDEX.index(char)]
return int_layout
def simulate(layout, max_x, max_y, wide=False):
max_seats_occupied = (5 if wide else 4)
new_layout = defaultdict(lambda: None)
for x in range(0, max_x):
for y in range(0, max_y):
if layout[(x, y)] is None:
continue
occupied_seats = 0
for cx in [x-1, x, x+1]:
for cy in [y-1, y, y+1]:
if cx == x and cy == y:
continue
check_value = layout[(cx, cy)]
if check_value is not None:
occupied_seats += check_value
elif wide:
test_x = cx + (cx - x)
test_y = cy + (cy - y)
while 0 <= test_x <= max_x and 0 <= test_y <= max_y:
if layout[(test_x, test_y)] is None:
test_x += (cx - x)
test_y += (cy - y)
else:
occupied_seats += layout[(test_x, test_y)]
break
if (layout[(x, y)] and occupied_seats >= max_seats_occupied) or (not layout[(x, y)] and occupied_seats == 0):
new_layout[(x, y)] = not layout[(x, y)]
else:
new_layout[(x, y)] = layout[(x, y)]
return new_layout
def part1(test_mode=False, wide=False):
my_input = aoclib.getInputAs2DArray(day=DAY, test=test_mode)
curr_layout = prepareLayout(my_input)
cellcount_x = len(my_input[0])
cellcount_y = len(my_input)
curr_occupied = 0
last_occupied = -1
generation_counter = 0
# Yes, this is relying on the assumption that there are no
# two different patterns with the same number of occupants.
while curr_occupied != last_occupied:
last_occupied = curr_occupied
generation_counter += 1
curr_layout = simulate(curr_layout, cellcount_x, cellcount_y, wide)
curr_occupied = sum(filter(None, curr_layout.values()))
print("Generations simulated: %d" % generation_counter)
return curr_occupied
def part2(test_mode=False):
return part1(test_mode, True)