-
Notifications
You must be signed in to change notification settings - Fork 0
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
- Loading branch information
Showing
5 changed files
with
206 additions
and
5 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,5 +1,5 @@ | ||
| # http://adventofcode.com/2021 | ||
| [workspace] | ||
| members = ["day*"] | ||
| exclude = ["day16", "day18"] | ||
| exclude = ["day18"] | ||
| resolver = "2" |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,11 @@ | ||
| [package] | ||
| name = "day16" | ||
| version = "0.1.0" | ||
| edition = "2021" | ||
|
|
||
| [dependencies] | ||
| aoc = { path = "../../aoc" } | ||
|
|
||
| [[bin]] | ||
| name = "day16" | ||
| path = "day16.rs" |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,190 @@ | ||
| //! [Day 16: Packet Decoder](https://adventofcode.com/2021/day/16) | ||
| fn int_value(bits: &str) -> u32 { | ||
| bits.chars() | ||
| .map_while(|c| c.to_digit(2)) | ||
| .fold(0, |acc, d| (acc << 1) + d) | ||
| } | ||
|
|
||
| fn read_packet(packet: &str, mut offset: usize, sum_of_versions: &mut u32) -> (usize, u64) { | ||
| assert!(offset < packet.len()); | ||
|
|
||
| let version = int_value(&packet[offset..offset + 3]); | ||
| let type_id = int_value(&packet[offset + 3..offset + 6]); | ||
| offset += 6; | ||
|
|
||
| // compute part 1 answer | ||
| *sum_of_versions += version; | ||
|
|
||
| // | ||
| if type_id == 4 { | ||
| let mut literal_value = 0; | ||
| loop { | ||
| let last = &packet[offset..=offset]; | ||
| let nibble = int_value(&packet[offset + 1..offset + 5]); | ||
| literal_value = (literal_value * 16) + u64::from(nibble); | ||
| offset += 5; | ||
| if offset > packet.len() || last == "0" { | ||
| return (offset, literal_value); | ||
| } | ||
| } | ||
| } | ||
|
|
||
| // subpackets | ||
| let mut values = Vec::new(); | ||
|
|
||
| // length of subpackets | ||
| let length_id = int_value(&packet[offset..=offset]); | ||
| offset += 1; | ||
|
|
||
| if length_id == 0 { | ||
| // | ||
| let length = int_value(&packet[offset..offset + 15]); | ||
| offset += 15; | ||
|
|
||
| let end_offset: usize = offset + usize::try_from(length).unwrap(); | ||
|
|
||
| while length != 0 && offset < end_offset { | ||
| let (new_offset, value) = read_packet(packet, offset, sum_of_versions); | ||
| values.push(value); | ||
| offset = new_offset; | ||
| } | ||
| } else { | ||
| let mut count = int_value(&packet[offset..offset + 11]); | ||
| offset += 11; | ||
|
|
||
| while count > 0 && offset < packet.len() { | ||
| let (new_offset, value) = read_packet(packet, offset, sum_of_versions); | ||
| values.push(value); | ||
| count -= 1; | ||
| offset = new_offset; | ||
| } | ||
| }; | ||
|
|
||
| let computed = match type_id { | ||
| 0 => values.iter().sum(), | ||
| 1 => values.iter().product(), | ||
| 2 => *values.iter().min().unwrap(), | ||
| 3 => *values.iter().max().unwrap(), | ||
| 5 => u64::from(values[0] > values[1]), | ||
| 6 => u64::from(values[0] < values[1]), | ||
| 7 => u64::from(values[0] == values[1]), | ||
| _ => panic!(), | ||
| }; | ||
|
|
||
| (offset, computed) | ||
| } | ||
|
|
||
| struct Puzzle { | ||
| part1: u32, | ||
| part2: u64, | ||
| } | ||
|
|
||
| impl Puzzle { | ||
| /// Get the puzzle input. | ||
| fn solve_from_file(path: &str) -> Self { | ||
| let data = std::fs::read_to_string(path).unwrap_or_else(|_| { | ||
| eprintln!("cannot read input file {path}"); | ||
| std::process::exit(1); | ||
| }); | ||
|
|
||
| Self::solve(&data) | ||
| } | ||
|
|
||
| fn solve(data: &str) -> Self { | ||
| let bin_data = data | ||
| .chars() | ||
| .map_while(|c| c.to_digit(16)) | ||
| .map(|d| match d { | ||
| 0 => "0000", | ||
| 1 => "0001", | ||
| 2 => "0010", | ||
| 3 => "0011", | ||
| 4 => "0100", | ||
| 5 => "0101", | ||
| 6 => "0110", | ||
| 7 => "0111", | ||
| 8 => "1000", | ||
| 9 => "1001", | ||
| 10 => "1010", | ||
| 11 => "1011", | ||
| 12 => "1100", | ||
| 13 => "1101", | ||
| 14 => "1110", | ||
| 15 => "1111", | ||
| _ => panic!(), | ||
| }) | ||
| .collect::<Vec<_>>() | ||
| .join(""); | ||
|
|
||
| let mut part1 = 0; | ||
| let (_, part2) = read_packet(&bin_data, 0, &mut part1); | ||
|
|
||
| Self { part1, part2 } | ||
| } | ||
| } | ||
|
|
||
| fn main() { | ||
| let args = aoc::parse_args(); | ||
| let puzzle = Puzzle::solve_from_file(args.path.as_str()); | ||
| println!("{}", puzzle.part1); | ||
| println!("{}", puzzle.part2); | ||
| } | ||
|
|
||
| /// Test from puzzle input | ||
| #[cfg(test)] | ||
| mod test { | ||
| use super::*; | ||
|
|
||
| #[test] | ||
| fn test_bin() { | ||
| assert_eq!(int_value("a"), 0); | ||
| assert_eq!(int_value("0"), 0); | ||
| assert_eq!(int_value("01"), 1); | ||
| assert_eq!(int_value("11"), 3); | ||
| assert_eq!(int_value("10000"), 16); | ||
| assert_eq!(int_value("10101010101010101010101010101010"), 0xAAAAAAAA); | ||
| } | ||
|
|
||
| #[test] | ||
| fn test_part1() { | ||
| let puzzle = Puzzle::solve("8A004A801A8002F478"); | ||
| assert_eq!(puzzle.part1, 16); | ||
|
|
||
| let puzzle = Puzzle::solve("620080001611562C8802118E34"); | ||
| assert_eq!(puzzle.part1, 12); | ||
|
|
||
| let puzzle = Puzzle::solve("C0015000016115A2E0802F182340"); | ||
| assert_eq!(puzzle.part1, 23); | ||
|
|
||
| let puzzle = Puzzle::solve("A0016C880162017C3686B18A3D4780"); | ||
| assert_eq!(puzzle.part1, 31); | ||
| } | ||
|
|
||
| #[test] | ||
| fn test_part2() { | ||
| let puzzle = Puzzle::solve("C200B40A82"); | ||
| assert_eq!(puzzle.part2, 3); | ||
|
|
||
| let puzzle = Puzzle::solve("04005AC33890"); | ||
| assert_eq!(puzzle.part2, 54); | ||
|
|
||
| let puzzle = Puzzle::solve("880086C3E88112"); | ||
| assert_eq!(puzzle.part2, 7); | ||
|
|
||
| let puzzle = Puzzle::solve("CE00C43D881120"); | ||
| assert_eq!(puzzle.part2, 9); | ||
|
|
||
| let puzzle = Puzzle::solve("D8005AC2A8F0"); | ||
| assert_eq!(puzzle.part2, 1); | ||
|
|
||
| let puzzle = Puzzle::solve("F600BC2D8F"); | ||
| assert_eq!(puzzle.part2, 0); | ||
|
|
||
| let puzzle = Puzzle::solve("9C005AC2F8F0"); | ||
| assert_eq!(puzzle.part2, 0); | ||
|
|
||
| let puzzle = Puzzle::solve("9C0141080250320F1802104A08"); | ||
| assert_eq!(puzzle.part2, 1); | ||
| } | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters