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|
import gleam/io
import gleam/int
import gleam/dict.{type Dict}
import gleam/list
import gleam/pair
import gleam/string as str
import gleam/iterator as iter
import ext/resultx as resx
import util/input_util
import util/graph
import util/parser as p
const bits: Int = 36
type Instr {
SetMem(address: String, value: Int)
ChangeMask(mask: String)
}
type Program =
List(Instr)
type Memory =
Dict(String, Int)
type State =
#(Memory, String)
fn parse_program(input: List(String)) -> Program {
let instr_parser =
p.or(
p.literal("mask = ")
|> p.proceed(with: p.any_str_greedy())
|> p.map(with: ChangeMask),
p.literal("mem[")
|> p.proceed(with: p.int())
|> p.map(with: fn(address) {
address
|> int.to_base_string(2)
|> resx.assert_unwrap
})
|> p.skip(p.literal("] = "))
|> p.then(p.int())
|> p.map2(with: SetMem),
)
input
|> list.map(with: fn(line) {
line
|> p.parse_entire(with: instr_parser)
|> resx.assert_unwrap
})
}
fn apply_mask(value: Int, mask: String) -> Int {
let or_mask =
mask
|> str.replace(each: "X", with: "0")
|> int.base_parse(2)
|> resx.assert_unwrap
let and_mask =
mask
|> str.replace(each: "X", with: "1")
|> int.base_parse(2)
|> resx.assert_unwrap
value
|> int.bitwise_or(or_mask)
|> int.bitwise_and(and_mask)
}
fn execute_program(
program: Program,
interpreter: fn(State, Instr) -> State,
) -> Int {
list.fold(
over: program,
from: #(dict.new(), "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"),
with: interpreter,
)
|> pair.first
|> dict.values
|> int.sum
}
fn memory_locations(from address: String, with mask: String) -> List(String) {
let address =
address
|> str.pad_left(to: bits, with: "0")
|> str.to_graphemes
|> list.zip(str.to_graphemes(mask))
|> list.map(with: fn(pair) {
let #(a, m) = pair
case m {
"0" -> a
"1" -> "1"
"X" -> "X"
_ -> panic
}
})
|> str.concat
#("", address)
|> graph.dfs(with: fn(prev) {
let #(done, queue) = prev
case str.pop_grapheme(queue) {
Error(Nil) -> iter.empty()
Ok(#(head, rest)) ->
case head {
"0" | "1" -> iter.single(#(done <> head, rest))
"X" -> iter.from_list([#(done <> "0", rest), #(done <> "1", rest)])
_ -> panic
}
}
})
|> iter.map(with: pair.first)
|> iter.filter(keeping: fn(res) { str.length(res) == bits })
|> iter.to_list
}
fn part1(input: List(String)) -> Int {
input
|> parse_program
|> execute_program(fn(acc, instr) {
let #(memory, mask) = acc
case instr {
SetMem(address, value) -> {
#(
memory
|> dict.insert(for: address, insert: apply_mask(value, mask)),
mask,
)
}
ChangeMask(new_mask) -> #(memory, new_mask)
}
})
}
fn part2(input: List(String)) -> Int {
input
|> parse_program
|> execute_program(fn(acc, instr) {
let #(memory, mask) = acc
case instr {
SetMem(address, value) -> {
#(
memory_locations(from: address, with: mask)
|> list.fold(from: memory, with: fn(memory, address) {
dict.insert(into: memory, for: address, insert: value)
}),
mask,
)
}
ChangeMask(new_mask) -> #(memory, new_mask)
}
})
}
pub fn main() -> Nil {
let testing = input_util.read_lines("test14")
let assert 51 = part1(testing)
let assert 208 = part2(testing)
let input = input_util.read_lines("day14")
io.debug(part1(input))
io.debug(part2(input))
Nil
}
|
