Files
aocpy/2021/d18.py
2024-11-24 18:50:28 -05:00

116 lines
2.9 KiB
Python

from lib import get_data
from math import ceil, floor
from itertools import combinations
data = """[[[0,[5,8]],[[1,7],[9,6]]],[[4,[1,2]],[[1,4],2]]]
[[[5,[2,8]],4],[5,[[9,9],0]]]
[6,[[[6,2],[5,6]],[[7,6],[4,7]]]]
[[[6,[0,7]],[0,9]],[4,[9,[9,0]]]]
[[[7,[6,4]],[3,[1,3]]],[[[5,5],1],9]]
[[6,[[7,3],[3,2]]],[[[3,8],[5,7]],4]]
[[[[5,4],[7,7]],8],[[8,3],8]]
[[9,3],[[9,9],[6,[4,9]]]]
[[2,[[7,7],7]],[[5,8],[[9,3],[0,2]]]]
[[[[5,2],5],[8,[3,7]]],[[5,[7,5]],[4,4]]]"""
data = get_data(__file__)
def parse(line):
xs = list(line)
for i in range(len(xs)):
try:
xs[i] = int(xs[i])
except ValueError:
pass
assert line == "".join(map(str, xs))
return xs
def reduce(xs):
reduced, nesting = False, 0
for i in range(len(xs)):
c = xs[i]
if c == "[" and nesting == 4 and not reduced:
lhs, rhs = xs[i + 1], xs[i + 3]
if not (type(lhs) is int and type(rhs) is int):
continue
xs = xs[:i] + [0] + xs[i + 5 :]
for j in range(i - 1, -1, -1):
if type(xs[j]) is int:
xs[j] += lhs
break
for j in range(i + 1, len(xs)):
if type(xs[j]) is int:
xs[j] += rhs
break
reduced = True
break
elif c == "[":
nesting += 1
elif c == "]":
nesting -= 1
if not reduced:
for i in range(len(xs)):
c = xs[i]
if type(c) is int and c >= 10:
p = [floor(c / 2), ceil(c / 2)]
xs = xs[:i] + ["[", p[0], ",", p[1], "]"] + xs[i + 1 :]
reduced = True
break
return xs
def restore(xs):
return "".join(map(str, xs))
assert restore(reduce(parse("[[[[[9,8],1],2],3],4]"))) == "[[[[0,9],2],3],4]"
assert restore(reduce(parse("[7,[6,[5,[4,[3,2]]]]]"))) == "[7,[6,[5,[7,0]]]]"
assert (
restore(reduce(parse("[[3,[2,[1,[7,3]]]],[6,[5,[4,[3,2]]]]]")))
== "[[3,[2,[8,0]]],[9,[5,[4,[3,2]]]]]"
)
assert (
restore(reduce(parse("[[3,[2,[8,0]]],[9,[5,[4,[3,2]]]]]")))
== "[[3,[2,[8,0]]],[9,[5,[7,0]]]]"
)
def add(a, b):
s = ["["] + a + [","] + b + ["]"]
while True:
ns = reduce(s)
if s == ns:
break
s = ns
return s
a = "[[[[4,3],4],4],[7,[[8,4],9]]]"
b = "[1,1]"
assert restore(add(parse(a), parse(b))) == "[[[[0,7],4],[[7,8],[6,0]]],[8,1]]"
lines = list(data.splitlines())
s = parse(lines[0].strip())
for line in lines[1:]:
s = add(s, parse(line.strip()))
def get_mag(xs):
if type(xs) is int:
return xs
return get_mag(xs[0]) * 3 + get_mag(xs[1]) * 2
print(get_mag(eval(restore(s))))
lines = list(data.splitlines())
m = 0
for a, b in combinations(lines, 2):
m = max(m, get_mag(eval(restore(add(parse(a), parse(b))))))
m = max(m, get_mag(eval(restore(add(parse(b), parse(a))))))
print(m)