Advent of Code 2017 #3

main.rs

#[derive(Debug, PartialEq, Copy, Clone)]
enum Dir {
    Up,
    Down,
    Left,
    Right,
}

#[derive(Clone, Copy, PartialEq)]
struct Point {
    x: i32,
    y: i32,
}

fn calc_position(val: u32) -> Point {
    let (mut point, mut dir) = (Point { x: 0, y: 0 }, Dir::Right);
    let (mut breakpoint, mut travel) = (2, 1);
    
    for i in 1..val {
        if i == breakpoint {
            // Increase travel when a corner is hit.
            if dir == Dir::Up || dir == Dir::Down {
                travel += 1;
            }
        
            // Choose new dir.
            dir = match dir {
                Dir::Up => Dir::Left,
                Dir::Down => Dir::Right,
                Dir::Left => Dir::Down,
                Dir::Right => Dir::Up,
            };
            
            // Set next breakpoint
            breakpoint = i + travel;
        }
        
        match dir {
            Dir::Up => point.y += 1,
            Dir::Down => point.y -= 1,
            Dir::Left => point.x -= 1,
            Dir::Right => point.x += 1,
        };
    }
    
    point
}

fn main() { // 361527
    let Point {x, y} = calc_position(361527);
    let answer = x + y;
    println!("X: {}, Y: {}; Answer = {}", x, y, answer);
}