def apply_to(self, num: ThirtySixBitNumber) -> list[ThirtySixBitNumber]:
if num in self.seen_applications:
return self.seen_applications[num]
number_of_copies = int(math.pow(2, self.number_of_xs_in_mask))
copies = [num.copy()] + ([num.copy()] * (number_of_copies - 1))
for i, m in enumerate(self.mask):
if m == "1":
for copy in copies:
copy.set_bit_in_place(i, 1)
seen_xs = 0
for index in range(0, 36):
if self.mask[index] != "X":
continue
# now repeat by 2^seen_xs across the list
# so 2^0 is 1 -> goes 01010101
# 2^1 is 2 -> goes 001100110011
# 2^2 is 4 -> goes 0000111100001111
for _ in range(0, number_of_copies):
pattern = [0] * pow(2, seen_xs) + [1] * pow(2, seen_xs)
pattern_generator = itertools.cycle(pattern)
for copy_index, copy in enumerate(copies):
copies[copy_index] = copy.set_bit(index, next(pattern_generator))
seen_xs += 1
self.seen_applications[num] = copies
return copies
def test_set_bits_in_place(self):
x = ThirtySixBitNumber(36)
y = x.set_bit(31, 1)
self.assertEqual(52, y.value)
z = x.set_bit_in_place(31, 1)
self.assertEqual(52, z.value)
self.assertEqual(52, x.value)
def process_line(self, line: str):
if line.startswith('mask'):
self.bitmask = VersionTwoBitMask(line.split(" = ")[1].strip())
elif line.startswith("mem"):
match = re.match(r"mem\[(\d+)] = (\d+)", line)
address = int(match.group(1))
num = ThirtySixBitNumber(int(match.group(2)))
decoded_addresses = self.bitmask.apply_to(ThirtySixBitNumber(address))
for decoded_address in decoded_addresses:
self.memory[decoded_address.value] = num.value
def test_v2_bitmask_x_writes_all_possibilities(self):
mask = VersionTwoBitMask("000000000000000000000000000000X1001X")
num = ThirtySixBitNumber(42)
results = mask.apply_to(num)
self.assertEqual(len(results), 4)
self.assertCountEqual(
results,
[
ThirtySixBitNumber(26),
ThirtySixBitNumber(27),
ThirtySixBitNumber(58),
ThirtySixBitNumber(59)
]
)
def test_apply_bitmask(self):
program = """
mask = XXXXXXXXXXXXXXXXXXXXXXXXXXXXX1XXXX0X
mem[8] = 11
mem[7] = 101
mem[8] = 0
"""
parsed_program = parse(program)
masked_program = apply_bitmask(parsed_program)
self.assertEqual(
masked_program, {
'mask':
BitMask("XXXXXXXXXXXXXXXXXXXXXXXXXXXXX1XXXX0X"),
'values': [(8, ThirtySixBitNumber(73)),
(7, ThirtySixBitNumber(101)),
(8, ThirtySixBitNumber(64))]
})
def test_parse_program(self):
program = """
mask = XXXXXXXXXXXXXXXXXXXXXXXXXXXXX1XXXX0X
mem[8] = 11
mem[7] = 101
mem[8] = 0
"""
parsed_program = parse(program)
print(parsed_program['values'])
self.assertEqual(
parsed_program, {
'mask':
BitMask("XXXXXXXXXXXXXXXXXXXXXXXXXXXXX1XXXX0X"),
'values': [(8, ThirtySixBitNumber(11)),
(7, ThirtySixBitNumber(101)),
(8, ThirtySixBitNumber(0))]
})
def test_example_values(self):
self.assertEqual(
ThirtySixBitNumber(73).bits, [
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1
])
self.assertEqual(
ThirtySixBitNumber(101).bits, [
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 1
])
self.assertEqual(
ThirtySixBitNumber(64).bits, [
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0
])
def test_can_create_number_from_bits(self):
n = ThirtySixBitNumber([
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1
])
self.assertEqual(n.bits, [
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1
])
self.assertEqual(3, n.value)
def test_v2_bitmask_zero_does_nothing(self):
mask = VersionTwoBitMask("000000000000000000000000000000000000")
bits = [0] * 36
bits[35] = 1
bits[34] = 0
num = ThirtySixBitNumber(bits)
actual = mask.apply_to(num)
self.assertEqual(actual[0].bits[35], 1)
self.assertEqual(actual[0].bits[34], 0)
def parse(program: str):
program_lines = [
line.strip() for line in program.splitlines() if len(line.strip()) > 0
]
instructions = []
for line in program_lines[1:]:
match = re.match(r"mem\[(\d+)] = (\d+)", line)
instructions.append(
(int(match.group(1)), ThirtySixBitNumber(int(match.group(2)))))
return {
'mask': BitMask(program_lines[0].split(" = ")[1].strip()),
'values': instructions
}
def test_v2_bitmask_one_writes_one(self):
mask = VersionTwoBitMask("000000000000000000000000000001010101")
bits = [0] * 36
num = ThirtySixBitNumber(bits)
actual = mask.apply_to(num)
self.assertEqual(len(actual), 1)
result = actual[0]
self.assertEqual(result.bits[35], 1)
self.assertEqual(result.bits[34], 0)
self.assertEqual(result.bits[33], 1)
self.assertEqual(result.bits[32], 0)
self.assertEqual(result.bits[31], 1)
self.assertEqual(result.bits[30], 0)
self.assertEqual(result.bits[29], 1)
def test_three(self):
n = ThirtySixBitNumber(3)
self.assertEqual(n.bits, [
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1
])
def test_two(self):
n = ThirtySixBitNumber(2)
self.assertEqual(n.bits, [
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0
])
def test_one(self):
n = ThirtySixBitNumber(1)
self.assertEqual(n.bits, [
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
])
def test_zero(self):
zero = ThirtySixBitNumber(0)
self.assertEqual(zero.bits, [
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
])
def test_bitmask_can_have_impact(self):
mask = BitMask("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX0X")
x = mask.apply_to(ThirtySixBitNumber(2))
self.assertEqual(x, ThirtySixBitNumber(0))