Improved Day 16 Part 1 by replacing strings with bitvec
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2f11a57ec2
commit
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@ -5,3 +5,52 @@ version = 3
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[[package]]
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name = "aoc2021"
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version = "0.1.0"
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dependencies = [
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"bitvec",
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"hex",
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]
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[[package]]
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name = "bitvec"
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version = "0.22.3"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "5237f00a8c86130a0cc317830e558b966dd7850d48a953d998c813f01a41b527"
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dependencies = [
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"funty",
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"radium",
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"tap",
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"wyz",
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]
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[[package]]
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name = "funty"
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version = "1.2.0"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "1847abb9cb65d566acd5942e94aea9c8f547ad02c98e1649326fc0e8910b8b1e"
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[[package]]
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name = "hex"
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version = "0.4.3"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "7f24254aa9a54b5c858eaee2f5bccdb46aaf0e486a595ed5fd8f86ba55232a70"
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[[package]]
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name = "radium"
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version = "0.6.2"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "643f8f41a8ebc4c5dc4515c82bb8abd397b527fc20fd681b7c011c2aee5d44fb"
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[[package]]
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name = "tap"
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version = "1.0.1"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "55937e1799185b12863d447f42597ed69d9928686b8d88a1df17376a097d8369"
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[[package]]
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name = "wyz"
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version = "0.4.0"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "129e027ad65ce1453680623c3fb5163cbf7107bfe1aa32257e7d0e63f9ced188"
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dependencies = [
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"tap",
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]
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@ -6,6 +6,8 @@ edition = "2021"
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# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
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[dependencies]
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bitvec = "0.22.3"
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hex = "0.4.3"
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[profile.release]
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@ -1 +1 @@
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9C0141080250320F1802104A08
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A0016C880162017C3686B18A3D4780
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272
src/main.rs
272
src/main.rs
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@ -1,72 +1,16 @@
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#![feature(test)]
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use std::collections::HashMap;
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extern crate test;
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use bitvec::view::BitView;
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type BitSlice<'a> = &'a bitvec::slice::BitSlice<bitvec::order::Msb0, u8>;
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const INPUTS: [&'static str; 2] = [
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include_str!("../inputs/sample.txt"),
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include_str!("../inputs/input.txt"),
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];
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fn parse_input(input: &'static str) -> String {
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let mapping = HashMap::from([
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('0', "0000"),
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('1', "0001"),
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('2', "0010"),
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('3', "0011"),
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('4', "0100"),
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('5', "0101"),
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('6', "0110"),
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('7', "0111"),
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('8', "1000"),
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('9', "1001"),
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('A', "1010"),
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('B', "1011"),
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('C', "1100"),
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('D', "1101"),
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('E', "1110"),
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('F', "1111"),
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]);
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let input = input.trim();
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let mut out = String::with_capacity(input.len() * 4);
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for c in input.chars() {
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let v = *mapping.get(&c).unwrap();
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out.push_str(v);
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}
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out
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}
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fn read_header(s: &mut impl Iterator<Item = char>) -> (u8, u8) {
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let raw_version: String = s.by_ref().take(3).collect();
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let version = u8::from_str_radix(&raw_version, 2).unwrap();
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let raw_type_id: String = s.take(3).collect();
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let type_id = u8::from_str_radix(&raw_type_id, 2).unwrap();
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(version, type_id)
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}
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fn read_literal(input: &mut impl Iterator<Item = char>) -> (u64, u64) {
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let mut out = String::new();
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let mut read = 0;
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loop {
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let last = input.next().unwrap() == '0';
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out.extend(input.take(4));
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read += 5;
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if last {
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break;
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}
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}
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(u64::from_str_radix(&out, 2).unwrap(), read)
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}
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#[derive(Debug)]
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struct PacketHeader {
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version: u8,
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type_id: u8,
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@ -77,121 +21,148 @@ struct Packet {
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header: PacketHeader,
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size: u64,
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literal: Option<u64>,
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sub_packets: Vec<Packet>,
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}
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impl Packet {
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fn value(&self) -> u64 {
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match self.header.type_id {
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0 => self.sub_packets.iter().fold(0, |a, x| a + x.value()),
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1 => self.sub_packets.iter().fold(1, |a, x| a * x.value()),
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2 => self.sub_packets.iter().map(|x| x.value()).min().unwrap(),
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3 => self.sub_packets.iter().map(|x| x.value()).max().unwrap(),
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4 => self.literal.unwrap(),
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5 => {
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let value1 = self.sub_packets[0].value();
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let value2 = self.sub_packets[1].value();
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fn new(input: &'static str) -> Self {
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let out = hex::decode(input).unwrap();
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if value1 > value2 {
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1
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} else {
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0
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}
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}
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6 => {
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let value1 = self.sub_packets[0].value();
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let value2 = self.sub_packets[1].value();
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let mut bvec: BitSlice = BitView::view_bits(out.as_slice());
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if value1 < value2 {
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1
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} else {
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0
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}
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}
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7 => {
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let value1 = self.sub_packets[0].value();
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let value2 = self.sub_packets[1].value();
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Self::parse(&mut bvec)
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}
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if value1 == value2 {
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1
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} else {
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0
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}
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fn read_literal(ip: &mut BitSlice) -> (u64, u64) {
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let mut out = 0;
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let mut read = 0;
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loop {
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let (word, remaining) = ip.split_at(5);
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*ip = remaining;
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read += 5;
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out = out << 4 | read_as_u8(&word[1..]) as u64;
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if !*word.first().unwrap() {
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break;
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}
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_ => unreachable!(),
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}
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(out, read)
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}
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fn read_header(ip: &mut BitSlice) -> (u8, u8) {
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(take_u8(ip, 3), take_u8(ip, 3))
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}
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fn parse(input: &mut BitSlice) -> Packet {
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let (version, type_id) = Self::read_header(input);
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let mut out = Packet {
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size: 6,
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literal: None,
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header: PacketHeader { version, type_id },
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sub_packets: vec![],
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};
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match type_id {
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// Literal
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4 => {
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let (literal, read) = Self::read_literal(input);
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out.size += read;
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out.literal = Some(literal);
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}
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// Operation
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_ => {
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let length_type_id = take_u8(input, 1);
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out.size += 1;
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match length_type_id {
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0 => {
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let mut trailing_packet_size = take_u64(input, 15);
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out.size += 15;
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while trailing_packet_size > 0 {
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let packet = Self::parse(input);
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trailing_packet_size -= packet.size;
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out.size += packet.size;
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out.sub_packets.push(packet);
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}
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}
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1 => {
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let trailing_packet_count = take_u64(input, 11);
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out.size += 11;
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for _ in 0..trailing_packet_count {
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let packet = Self::parse(input);
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out.size += packet.size;
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out.sub_packets.push(packet);
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}
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}
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_ => unreachable!(),
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}
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}
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};
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out
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}
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}
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fn read_packet(input: &mut impl Iterator<Item = char>) -> Packet {
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let (version, type_id) = read_header(input);
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fn take_u8(ip: &mut BitSlice, offset: usize) -> u8 {
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let (num, left) = ip.split_at(offset);
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*ip = left;
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let mut out = Packet {
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size: 6,
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literal: None,
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header: PacketHeader { version, type_id },
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sub_packets: vec![],
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};
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read_as_u8(num)
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}
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match type_id {
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// Literal
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4 => {
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let (literal, read) = read_literal(input);
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fn take_u64(ip: &mut BitSlice, offset: usize) -> u64 {
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let (num, left) = ip.split_at(offset);
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*ip = left;
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out.size += read;
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out.literal = Some(literal);
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}
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read_as_u64(num)
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}
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// Operation
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_ => {
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let length_type_id = input.next().unwrap();
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out.size += 1;
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fn read_as_u64(ip: BitSlice) -> u64 {
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let mut out = 0;
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match length_type_id {
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'0' => {
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let mut trailing_packet_size =
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u64::from_str_radix(&input.take(15).collect::<String>(), 2).unwrap();
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out.size += 15;
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for bit in ip {
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out = out << 1 | if *bit { 1 } else { 0 };
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}
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while trailing_packet_size > 0 {
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let packet = read_packet(input);
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trailing_packet_size -= packet.size;
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out.size += packet.size;
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out.sub_packets.push(packet);
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}
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}
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'1' => {
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let trailing_packet_count =
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usize::from_str_radix(&input.take(11).collect::<String>(), 2).unwrap();
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out.size += 11;
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for _ in 0..trailing_packet_count {
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let packet = read_packet(input);
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out.size += packet.size;
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out.sub_packets.push(packet);
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}
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}
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_ => unreachable!(),
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}
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}
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};
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out
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}
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fn solution(input: String) -> u64 {
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let mut input = input.chars();
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let packet = read_packet(&mut input);
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fn read_as_u8(ip: BitSlice) -> u8 {
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let mut out = 0;
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packet.value()
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for bit in ip {
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out = out << 1 | if *bit { 1 } else { 0 };
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}
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out
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}
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fn solution(input: &'static str) -> u64 {
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let packet = Packet::new(input.trim());
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let mut stack = vec![packet];
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let mut answer = 0;
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while let Some(packet) = stack.pop() {
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answer += packet.header.version as u64;
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stack.extend(packet.sub_packets);
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}
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answer
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}
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fn main() {
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for input in INPUTS {
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let input = parse_input(input);
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let result = solution(input);
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println!("Result = {}", result);
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}
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@ -199,9 +170,8 @@ fn main() {
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#[bench]
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fn solution_bench(b: &mut test::Bencher) {
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let input = parse_input(INPUTS[1]);
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b.iter(|| {
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let result = solution(input.clone());
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let result = solution(INPUTS[1]);
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test::black_box(result);
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})
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}
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