from helpers import * lines = read_day(15).split('\n') sample_lines = ''' Sensor at x=2, y=18: closest beacon is at x=-2, y=15 Sensor at x=9, y=16: closest beacon is at x=10, y=16 Sensor at x=13, y=2: closest beacon is at x=15, y=3 Sensor at x=12, y=14: closest beacon is at x=10, y=16 Sensor at x=10, y=20: closest beacon is at x=10, y=16 Sensor at x=14, y=17: closest beacon is at x=10, y=16 Sensor at x=8, y=7: closest beacon is at x=2, y=10 Sensor at x=2, y=0: closest beacon is at x=2, y=10 Sensor at x=0, y=11: closest beacon is at x=2, y=10 Sensor at x=20, y=14: closest beacon is at x=25, y=17 Sensor at x=17, y=20: closest beacon is at x=21, y=22 Sensor at x=16, y=7: closest beacon is at x=15, y=3 Sensor at x=14, y=3: closest beacon is at x=15, y=3 Sensor at x=20, y=1: closest beacon is at x=15, y=3 '''.strip().split('\n') def do_sensors(lines: list[str], row: int): seen_cells_on_row = set() for line in lines: x, y, nx, ny = line_to_numbers(line) distance = abs(x-nx) + abs(y-ny) dr = abs(y-row) if dr < distance: d2 = distance - dr seen_cells_on_row |= {x+i for i in range(-d2, d2+1)} print(f'Part 1: {len(seen_cells_on_row) - 1}') # do_sensors(sample_lines, 20) do_sensors(lines, 2_000_000) def do_sensors_2(lines: list[str], search_space: int): sensors = [] for line in lines: x, y, nx, ny = line_to_numbers(line) distance = abs(x-nx) + abs(y-ny) sensors.append((x, y, distance)) sensors.sort(key=lambda x: x[2]) # smallest distance first def in_range_of_sensors(x: int, y: int) -> bool: if not (0 <= x <= search_space and 0 <= y <= search_space): return True for (i,j,d) in sensors: if abs(x-i) + abs(y-j) <= d: return True print(f'Part 2: Seen at ({x},{y}) = submit {x*4_000_000 + y}') return False # print(sensors) for x0, y0, d in sensors: # Iterate around perimeters # print(x0, y0, d) y_up = y0 + d + 1 y_down = y0 - d - 1 for i in range(d+1): for x in (x0+i, x0-i): for y in (y_down+i, y_up-i): if not in_range_of_sensors(x, y): return # do_sensors_2(sample_lines, 20) do_sensors_2(lines, 4_000_000)