aoc15.rs

fn main() {
    let fs = std::fs::read_to_string("in.txt").unwrap();
    let mut sensors = vec![];
    for line in fs.lines() {
        let mut parts = line.split_whitespace();
        let sensor: (i32, i32) = (parts.nth(2).unwrap().trim_matches(|c| c == 'x' || c == '=' || c == ',').parse().unwrap(),
                                  parts.next().unwrap().trim_matches(|c| c == 'y' || c == '=' || c == ':').parse().unwrap());
        let beacon: (i32, i32) = (parts.nth(4).unwrap().trim_matches(|c| c == 'x' || c == '=' || c == ',').parse().unwrap(),
                                    parts.nth(0).unwrap().trim_matches(|c| c == 'y' || c == '=' || c == ',').parse().unwrap());
        let distance = (sensor.0 - beacon.0).abs() + (sensor.1 - beacon.1).abs();

        sensors.push((sensor.0, sensor.1, distance));
    }

    let mut events = Vec::with_capacity(2 * sensors.len());

    for y in 0..4000000 {
        events.clear();
        for (sx, sy, distance) in &sensors {
            let diffy = (sy - y).abs();

            if diffy > *distance {
                continue;
            }

            let span = distance - diffy;

            events.push((sx - span, true));
            events.push((sx + span + 1, false));
        }

        events.sort_by_key(|e| e.0);

        let mut countopen = 0;
        for i in 0..events.len() {
            let (x, open) = events[i];

            if open {
                countopen += 1;
            } else {
                countopen -= 1;
            }
            if !open && ((i == events.len() - 1) || events[i+1].0 != x) && countopen == 0 && x >= 0 && x <= size {
                println!("{} {} {}", x, y, x as i64 * 4000000 + y as i64);
            }
        }
    }
}