Table of content

What is this
32nd Challenge
- Challenge
- Solution

What is this

The rules of the game are explained in my original post.

32nd Challenge

Challenge

Today I’m solving today’s AoC day 2 2021. Only got around to doing this after work .

Solution

It has become a bit verbose, but its quite readable, here goes.

	fn main() {

	    let parsed_input:Vec<(&str, i32)> = INPUT.lines()
	        .map(|x|{x.split_once(" ").unwrap()})
	        .map(|x|{(x.0,x.1.parse::<i32>().unwrap())})
	        .collect();

	    let mut pos = Position{ x: 0, y: 0 };

	    pos.y += parsed_input.iter()
	        .filter(|x|{x.0 == "up"})
	        .fold(0,|acc, c| { acc + c.1 });

	    pos.y -= parsed_input.iter()
	        .filter(|x|{x.0 == "down"})
	        .fold(0,|acc, c| { acc + c.1 });

	    pos.x += parsed_input.iter()
	        .filter(|x|{x.0 == "forward"})
	        .fold(0,|acc, c| { acc + c.1 });

	    pos.print();

	    let aim_delta:Vec<i32> = parsed_input.iter()
	        .map(|x| { match x.0 {
	            "up" => -x.1,
	            "down" => x.1,
	            _ => 0
	        }})
	        .collect();

	    let out:Vec<i32> = parsed_input.iter()
	        .map(|x|{ match x.0 {
	            "forward" => x.1,
	            _ => 0
	        }})
	        .collect();

	     let pos = out.iter()
	         .zip(aim_delta.iter())
	         .fold((0,Position{x:0,y:0}),|mut acc, x|{
	             acc.1.x += x.0;
	             acc.1.y += acc.0*x.0;
	             acc.0 -= x.1;
	             acc
	         }).1;

	    pos.print();

	}

	struct Position{
	    x:i32,
	    y:i32
	}

	impl Position{
	    fn print(&self){
	        println!(" x = {} , y = {}, depth = {}, x * depth = {}",self.x,self.y,-self.y,-self.x*self.y);
	    }
	}


	const INPUT:&str = "forward 5
	down 5
	forward 8
	up 3
	down 8
	forward 2";

To see the full source see github and see the live demo in playground.

My favorite solution can be seen by clicking here.