diff options
Diffstat (limited to '2017/src/bin/day_21.rs')
| -rw-r--r-- | 2017/src/bin/day_21.rs | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/2017/src/bin/day_21.rs b/2017/src/bin/day_21.rs new file mode 100644 index 0000000..7f7ac79 --- /dev/null +++ b/2017/src/bin/day_21.rs @@ -0,0 +1,200 @@ +extern crate advent_of_code_2017; +use advent_of_code_2017::*; + +extern crate regex; +use regex::Regex; + +fn main() { + let args = AdventArgs::init(); + + let (t2, t3) = parse_transforms(&args.input); + + let mut picture = vec!( + vec!(false, true, false), + vec!(false, false, true), + vec!(true, true, true) + ); + + let iterations = if args.part == 1 { + 5 + } else { + 18 + }; + for _ in 0..iterations { + picture = expand(&picture, &t2, &t3); + } + + let ones: usize = picture.iter().map( + |row| row.iter().filter(|&&x| x).count() + ).sum(); + println!("{} ones", ones); +} + +fn print(picture: &Vec<Vec<bool>>) { + for row in picture { + for &c in row { + print!("{}", if c {"#"} else {"."}); + } + println!(); + } + println!(); +} + +fn expand(picture: &Vec<Vec<bool>>, t2: &Vec<Transform2>, t3: &Vec<Transform3>) -> Vec<Vec<bool>> { + let size = picture.len(); + let div = if size % 2 == 0 { 2 } else { 3 }; + let segments = size / div; + let new_size = size + segments; + + let mut result = vec!(vec!(false; new_size); new_size); + + for i in 0..segments { + let y = i*div; + let v = i*(div+1); + for j in 0..segments { + let x = j*div; + let u = j*(div+1); + if div == 2 { + let init = [ + [picture[y][x], picture[y][x+1]], + [picture[y+1][x], picture[y+1][x+1]] + ]; + let pattern = t2.iter().find(|p| p.matches(&init)).expect(&format!("No pattern matches {:?}", init)); + let to = pattern.to; + + for a in 0..div+1 { + for b in 0..div+1 { + result[v+a][u+b] = to[a][b]; + } + } + } else { + let init = [ + [picture[y][x], picture[y][x+1], picture[y][x+2]], + [picture[y+1][x], picture[y+1][x+1], picture[y+1][x+2]], + [picture[y+2][x], picture[y+2][x+1], picture[y+2][x+2]] + ]; + let pattern = t3.iter().find(|p| p.matches(&init)).expect(&format!("No pattern matches {:?}", init)); + let to = pattern.to; + + for a in 0..div+1 { + for b in 0..div+1 { + result[v+a][u+b] = to[a][b]; + } + } + } + } + } + + result +} + +fn parse_transforms(input: &Vec<String>) -> (Vec<Transform2>, Vec<Transform3>) { + let t2_re = Regex::new(r"^(.)(.)/(.)(.) => (.)(.)(.)/(.)(.)(.)/(.)(.)(.)$").unwrap(); + let t3_re = Regex::new(r"^(.)(.)(.)/(.)(.)(.)/(.)(.)(.) => (.)(.)(.)(.)/(.)(.)(.)(.)/(.)(.)(.)(.)/(.)(.)(.)(.)$").unwrap(); + + let mut t2 = Vec::new(); + let mut t3 = Vec::new(); + for line in input { + if let Some(t2_caps) = t2_re.captures(line) { + t2.push(Transform2 { + from: [ + [&t2_caps[1] == "#", &t2_caps[2] == "#"], + [&t2_caps[3] == "#", &t2_caps[4] == "#"] + ], + to: [ + [&t2_caps[5] == "#", &t2_caps[6] == "#", &t2_caps[7] == "#"], + [&t2_caps[8] == "#", &t2_caps[9] == "#", &t2_caps[10] == "#"], + [&t2_caps[11] == "#", &t2_caps[12] == "#", &t2_caps[13] == "#"] + ] + }); + } else if let Some(t3_caps) = t3_re.captures(line) { + t3.push(Transform3 { + from: [ + [&t3_caps[1] == "#", &t3_caps[2] == "#", &t3_caps[3] == "#"], + [&t3_caps[4] == "#", &t3_caps[5] == "#", &t3_caps[6] == "#"], + [&t3_caps[7] == "#", &t3_caps[8] == "#", &t3_caps[9] == "#"] + ], + to: [ + [&t3_caps[10] == "#", &t3_caps[11] == "#", &t3_caps[12] == "#", &t3_caps[13] == "#"], + [&t3_caps[14] == "#", &t3_caps[15] == "#", &t3_caps[16] == "#", &t3_caps[17] == "#"], + [&t3_caps[18] == "#", &t3_caps[19] == "#", &t3_caps[20] == "#", &t3_caps[21] == "#"], + [&t3_caps[22] == "#", &t3_caps[23] == "#", &t3_caps[24] == "#", &t3_caps[25] == "#"] + ] + }); + } + } + + (t2, t3) +} + +#[derive(Debug)] +struct Transform2 { + from: [[bool; 2]; 2], + to: [[bool; 3]; 3] +} + +impl Transform2 { + fn rotate(from: &[[bool;2];2]) -> [[bool;2];2] { + [ + [from[1][0],from[0][0]], + [from[1][1],from[0][1]] + ] + } + + fn flip(from: &[[bool;2];2]) -> [[bool;2];2] { + [ + [from[0][1],from[0][0]], + [from[1][1],from[1][0]] + ] + } + + fn matches(&self, other: &[[bool; 2]; 2]) -> bool { + let mut any_match = false; + let mut spinning_other = other.clone(); + for _ in 0..4 { + any_match = any_match || + self.from == spinning_other || + self.from == Transform2::flip(&spinning_other); + + spinning_other = Transform2::rotate(&spinning_other); + } + any_match + } +} + +#[derive(Debug)] +struct Transform3 { + from: [[bool; 3]; 3], + to: [[bool; 4]; 4] +} + +impl Transform3 { + fn rotate(from: &[[bool;3];3]) -> [[bool;3];3] { + [ + [from[2][0],from[1][0],from[0][0]], + [from[2][1],from[1][1],from[0][1]], + [from[2][2],from[1][2],from[0][2]] + ] + } + + fn flip(from: &[[bool;3];3]) -> [[bool;3];3] { + [ + [from[0][2],from[0][1],from[0][0]], + [from[1][2],from[1][1],from[1][0]], + [from[2][2],from[2][1],from[2][0]] + ] + } + + fn matches(&self, other: &[[bool; 3]; 3]) -> bool { + let mut any_match = false; + let mut spinning_other = other.clone(); + for _ in 0..4 { + any_match = any_match || + self.from == spinning_other || + self.from == Transform3::flip(&spinning_other); + + spinning_other = Transform3::rotate(&spinning_other); + } + any_match + } +} |