Files
advent-of-code-go/2024/day24/day24.py
T
2024-12-31 14:53:29 -05:00

251 lines
7.8 KiB
Python

from collections import defaultdict
import copy
def part1(input: str) -> int:
wires, instructions = parse_input(input)
run(instructions, wires)
return get_num(wires, "z")
def parse_input(input: str) -> tuple[dict[str, int], list[list[str]]]:
parts = input.split("\n\n")
wires: dict[str, int] = defaultdict(int)
for line in parts[0].splitlines():
wires[line[:3]] = int(line[5:])
instructions: list[list[str]] = []
for line in parts[1].splitlines():
in1, op, in2, _, out = line.split(" ")
instructions.append([in1, op, in2, out])
return (wires, instructions)
def get_num(wires: dict[str, int], char: str) -> int:
if len(char) != 1:
raise Exception("exactly one char needed for get_num")
keys: list[str] = []
for wire in wires:
if wire[0] == char:
keys.append(wire)
keys.sort()
binary_num: str = ""
for key in reversed(keys):
binary_num += str(wires[key])
return int(binary_num, 2)
def run(instructions: list[list[str]], wires: dict[str, int]):
processed_lines: set[int] = set()
while len(processed_lines) < len(instructions):
processed_before: int = len(processed_lines)
for i, inst in enumerate(instructions):
if i in processed_lines:
continue
in1, op, in2, out = inst
if in1 not in wires or in2 not in wires:
continue
if op == "AND":
wires[out] = wires[in1] & wires[in2]
elif op == "OR":
wires[out] = wires[in1] | wires[in2]
elif op == "XOR":
wires[out] = wires[in1] ^ wires[in2]
processed_lines.add(i)
if len(processed_lines) == processed_before:
# print("no new lines processed")
return
# this code is way too slow, works for the examples but unsurprisingly way too
# slow for the actual input. ditching python for a go solution...
def part2(input: str) -> str:
wires, instructions = parse_input(input)
expected_sum: int = get_num(wires, "x") & get_num(wires, "y")
def any_values_are_equal(*args: int) -> bool:
seen: set[int] = set()
for val in args:
if val in seen:
return True
seen.add(val)
return False
# generate swaps... maybe 8 nested for loops...
for a in range(len(instructions)):
print(a)
for b in range(a + 1, len(instructions)):
for c in range(a + 1, len(instructions)):
if any_values_are_equal(b, c):
continue
for d in range(a + 1, len(instructions)):
if any_values_are_equal(b, c, d):
continue
for e in range(a + 1, len(instructions)):
if any_values_are_equal(b, c, d, e):
continue
for f in range(a + 1, len(instructions)):
if any_values_are_equal(b, c, d, e, f):
continue
for g in range(a + 1, len(instructions)):
if any_values_are_equal(b, c, d, e, f, g):
continue
for h in range(a + 1, len(instructions)):
if any_values_are_equal(b, c, d, e, f, g, h):
continue
instructions[a][3], instructions[b][3] = (
instructions[b][3],
instructions[a][3],
)
instructions[c][3], instructions[d][3] = (
instructions[d][3],
instructions[c][3],
)
instructions[e][3], instructions[f][3] = (
instructions[f][3],
instructions[e][3],
)
instructions[g][3], instructions[h][3] = (
instructions[h][3],
instructions[g][3],
)
wires_copy = copy.deepcopy(wires)
run(instructions, wires_copy)
sum = get_num(wires_copy, "z")
if sum == expected_sum:
swaps: list[str] = [
instructions[a][3],
instructions[b][3],
instructions[c][3],
instructions[d][3],
instructions[e][3],
instructions[f][3],
instructions[g][3],
instructions[h][3],
]
swaps.sort()
return ",".join(swaps)
# backtrack
instructions[a][3], instructions[b][3] = (
instructions[b][3],
instructions[a][3],
)
instructions[c][3], instructions[d][3] = (
instructions[d][3],
instructions[c][3],
)
instructions[e][3], instructions[f][3] = (
instructions[f][3],
instructions[e][3],
)
instructions[g][3], instructions[h][3] = (
instructions[h][3],
instructions[g][3],
)
raise Exception("should return from loop")
example = """x00: 1
x01: 1
x02: 1
y00: 0
y01: 1
y02: 0
x00 AND y00 -> z00
x01 XOR y01 -> z01
x02 OR y02 -> z02"""
print(f"part1 example: {part1(example)} want 4")
big_example = """x00: 1
x01: 0
x02: 1
x03: 1
x04: 0
y00: 1
y01: 1
y02: 1
y03: 1
y04: 1
ntg XOR fgs -> mjb
y02 OR x01 -> tnw
kwq OR kpj -> z05
x00 OR x03 -> fst
tgd XOR rvg -> z01
vdt OR tnw -> bfw
bfw AND frj -> z10
ffh OR nrd -> bqk
y00 AND y03 -> djm
y03 OR y00 -> psh
bqk OR frj -> z08
tnw OR fst -> frj
gnj AND tgd -> z11
bfw XOR mjb -> z00
x03 OR x00 -> vdt
gnj AND wpb -> z02
x04 AND y00 -> kjc
djm OR pbm -> qhw
nrd AND vdt -> hwm
kjc AND fst -> rvg
y04 OR y02 -> fgs
y01 AND x02 -> pbm
ntg OR kjc -> kwq
psh XOR fgs -> tgd
qhw XOR tgd -> z09
pbm OR djm -> kpj
x03 XOR y03 -> ffh
x00 XOR y04 -> ntg
bfw OR bqk -> z06
nrd XOR fgs -> wpb
frj XOR qhw -> z04
bqk OR frj -> z07
y03 OR x01 -> nrd
hwm AND bqk -> z03
tgd XOR rvg -> z12
tnw OR pbm -> gnj"""
print(f"part1 big_example: {part1(big_example)} want 2024")
input = open("input.txt").read().strip()
print(f"part1 actual: {part1(input)} want 38869984335432")
part2_example_2_pairs_swapped = """x00: 0
x01: 1
x02: 0
x03: 1
x04: 0
x05: 1
y00: 0
y01: 0
y02: 1
y03: 1
y04: 0
y05: 1
x00 AND y00 -> z05
x01 AND y01 -> z02
x02 AND y02 -> z01
x03 AND y03 -> z03
x04 AND y04 -> z04
x05 AND y05 -> z00"""
# print(
# f"part2 example with two swapped {part2(part2_example_2_pairs_swapped)} want z00,z01,z02,z05"
# )
print(f"part2 actual: {part2(input)} want QQ")