diff options
Diffstat (limited to '2018/src')
| -rw-r--r-- | 2018/src/day10.rs | 73 | ||||
| -rw-r--r-- | 2018/src/main.rs | 4 |
2 files changed, 76 insertions, 1 deletions
diff --git a/2018/src/day10.rs b/2018/src/day10.rs new file mode 100644 index 0000000..28da8de --- /dev/null +++ b/2018/src/day10.rs @@ -0,0 +1,73 @@ +use std::io; +use std::io::BufRead; +use std::collections::HashSet; + +fn parse_pt(l: &str) -> ((i32, i32), (i32, i32)) { + let i1 = l.find('<').unwrap(); + let i2 = l[i1..].find(',').unwrap() + i1; + let i3 = l[i2..].find('>').unwrap() + i2; + let i4 = l[i3..].find('<').unwrap() + i3; + let i5 = l[i4..].find(',').unwrap() + i4; + let i6 = l[i5..].find('>').unwrap() + i5; + + let s1 = &l[i1+1..i2]; + let s2 = &l[i2+1..i3]; + let s3 = &l[i4+1..i5]; + let s4 = &l[i5+1..i6]; + + ((s1.trim().parse().unwrap(), s2.trim().parse().unwrap()), + (s3.trim().parse().unwrap(), s4.trim().parse().unwrap())) +} + +pub fn main<T: BufRead>(reader: T) -> io::Result<(String, String)> { + let dots: Vec<((i32, i32), (i32, i32))> = + reader.lines().map(|l| l.unwrap()) + .map(|l| parse_pt(&l)) + .collect(); + + let mut pts: Vec<_> = dots.iter().map(|&(xy, _)| xy).collect(); + let vels: Vec<_> = dots.iter().map(|&(_, v)| v).collect(); + + let mut maxscore = -1; + let mut maxat = (-1, vec![], HashSet::new()); + for iter in 0..20000 { + let mut has_dot: HashSet<(i32, i32)> = HashSet::new(); + let mut score = 0; + for &xy in &pts { + if has_dot.contains(&xy) { score += 1; } + has_dot.insert(xy); + } + + if score > maxscore { + maxscore = score; + maxat = (iter, pts.clone(), has_dot.clone()); + if maxscore > dots.len() as i32 / 2 { + break; + } + } + + for i in 0..dots.len() { + pts[i].0 += vels[i].0; + pts[i].1 += vels[i].1; + } + } + + let mut part1 = String::new(); + + let part2 = maxat.0.to_string(); + let pts = maxat.1; + let has_dot = maxat.2; + let minx = pts.iter().map(|&(x, _)| x).min().unwrap(); + let miny = pts.iter().map(|&(_, y)| y).min().unwrap(); + let maxx = pts.iter().map(|&(x, _)| x).max().unwrap(); + let maxy = pts.iter().map(|&(_, y)| y).max().unwrap(); + for y in miny..maxy+1 { + if y != miny { part1 += "\n"; } + for x in minx..maxx + 1 { + if has_dot.contains(&(x, y)) { part1 += "#"; } + else { part1 += "."; } + } + } + + Ok((part1, part2)) +} diff --git a/2018/src/main.rs b/2018/src/main.rs index 70e7a79..3e9756b 100644 --- a/2018/src/main.rs +++ b/2018/src/main.rs @@ -14,8 +14,9 @@ mod day6; mod day7; mod day8; mod day9; +mod day10; -static NUM_DAYS: i32 = 9; +static NUM_DAYS: i32 = 10; fn day_switch<T: BufRead>(day: i32, reader: T) -> io::Result<(String, String)> { match day { @@ -28,6 +29,7 @@ fn day_switch<T: BufRead>(day: i32, reader: T) -> io::Result<(String, String)> { 7 => day7::main(reader), 8 => day8::main(reader), 9 => day9::main(reader), + 10 => day10::main(reader), _ => Err(Error::new(ErrorKind::Other, "Invalid day")) } } |