aoc/day6/src/main.rs

use std::collections::HashMap;

fn copy_to_array(a: &mut [char; 3], b: &str) {
    assert_eq!(b.len(), 3);
    let mut x = 0;
    for c in b.chars() {
        a[x] = c;
        x += 1;
    }
}

fn main() {
    {
        let test_map = get_map_from_file("test");
        assert_eq!(test_map.get("COM").unwrap().distance_to_com(&test_map), 0);
        assert_eq!(test_map.get("B").unwrap().distance_to_com(&test_map), 1);
        assert_eq!(test_map.get("D").unwrap().distance_to_com(&test_map), 3);
        assert_eq!(test_map.get("L").unwrap().distance_to_com(&test_map), 7);
        let f_parents = test_map.get("F").unwrap().parents(&test_map);
        assert_eq!(f_parents, vec!["E", "D", "C", "B", "COM"]);
        let l_parents = test_map.get("L").unwrap().parents(&test_map);
        assert_eq!(l_parents, vec!["K", "J", "E", "D", "C", "B", "COM"]);
        assert_eq!(first_common(f_parents, l_parents), "E");
        let mut x: i32 = 0;
        for val in test_map.values() {
            x += val.distance_to_com(&test_map);
        }
        assert_eq!(x, 42);
    }

    {
        let test_map2 = get_map_from_file("test2");
        let you = test_map2.get("YOU").unwrap();
        let san = test_map2.get("SAN").unwrap();
        println!("{:?}", you);
        println!("{:?}", san);
        println!("{:?}", you.parents(&test_map2));
        println!("{:?}", san.parents(&test_map2));
        let parent = first_common(you.parents(&test_map2), san.parents(&test_map2));
        println!("First common parent of YOU and SAN: '{}'", parent);
        println!("Distance from YOU to {}: {}", parent, you.distance_to(&parent, &test_map2));
        println!("Distance from SAN to {}: {}", parent, san.distance_to(&parent, &test_map2));

        println!("[Test2] Transfers required to go from YOU to SAN: {}",
                 you.distance_to(&parent, &test_map2) + san.distance_to(&parent, &test_map2) - 2);
    }

    let map = get_map_from_file("input");
    let mut x: i32 = 0;
    for val in map.values() {
        x += val.distance_to_com(&map);
    }
    println!("[Part 1] Total indirect and direct orbits: {}", x);

    let you = map.get("YOU").unwrap();
    let you_parents = you.parents(&map);
    let san = map.get("SAN").unwrap();
    let san_parents = san.parents(&map);
    let common_parent = first_common(you_parents, san_parents);
    println!("First common parent of YOU and SAN: '{}'", common_parent);
    println!("Distance from YOU to {}: {}", common_parent, you.distance_to(&common_parent, &map));
    println!("Distance from SAN to {}: {}", common_parent, san.distance_to(&common_parent, &map));
    println!("[Part 2] Transfers required to go from YOU to SAN: {}",
             you.distance_to(&common_parent, &map) + san.distance_to(&common_parent, &map) - 2);
}

fn first_common(a: Vec<String>, b: Vec<String>) -> String {
    let mut x: Option<usize> = None;
    for v_a in a.iter() {
        let mut iter: usize = 0;
        for v_b in b.iter() {
            if v_a == v_b {
                x = Some(iter);
                break;
            }
            iter += 1;
        }
        if x.is_some() {
            break;
        }
    }
    return b[x.unwrap()].clone();
}

fn get_map_from_file(file: &str) -> HashMap<String, Node> {
    let contents = std::fs::read_to_string(file)
        .expect("Failed to read file 'input'");
    let it = contents.split("\n");
    let mut map: HashMap<String, Node> = HashMap::new();
    for line in it {
        let s = String::from(line);
        s.trim();
        if s.is_empty() {
            break;
        }
        {
            let values: Vec<&str> = s.split(")").collect();
            //println!("Line: {}", line);
            assert_eq!(values.len(), 2);
            //assert_eq!(values[0].len(), 3);
            //assert_eq!(values[1].len(), 3);
            for v in values {
                if !map.contains_key(v) {
                    let n = Node {
                        id: v.to_string(),
                        parent: None,
                        children: Vec::new(),
                    };
                    map.insert(v.to_string(), n);
                }
            }
        }
        let values: Vec<&str> = s.split(")").collect();
        {
            let mut node = map.get_mut(values[1]).unwrap();
            if !node.parent.is_some() {
                node.parent = Some(values[0].to_string());
            }
        }
        {
            let mut node = map.get_mut(values[0]).unwrap();
            if !node.children.contains(&values[1].to_string()) {
                node.children.push(values[1].to_string());
            }
        }
    }
    return map;
}

#[derive(Debug)]
struct Node {
    parent: Option<String>,
    id: String,
    children: Vec<String>,
}

impl Node {

    fn distance_to(&self, to: &str, map: &HashMap<String, Node>) -> i32 {
        if self.id == to {
            return 0;
        }
        let parent = self.parent.as_ref().unwrap().clone();
        return map.get(&parent).unwrap().distance_to(to, map) + 1;
    }

    fn distance_to_com(&self, map: &HashMap<String, Node>) -> i32 {
        return self.distance_to("COM", map);
    }

    fn parents(&self, map: &HashMap<String, Node>) -> Vec<String> {
        let mut parents: Vec<String> = Vec::new();
        if self.parent.is_some() {
            parents.push(self.parent.as_ref().unwrap().clone());
            let parent = map.get(&self.parent.as_ref().unwrap().clone()).unwrap();
            for v in parent.parents(map) {
                parents.push(v);
            }
        }
        return parents;
    }

}

impl PartialEq for Node {
    fn eq(&self, other: &Self) -> bool {
        self.id == other.id
    }
}