1 files changed, 198 insertions, 0 deletions
diff --git a/2016/aoc22/src/main.rs b/2016/aoc22/src/main.rs
new file mode 100644
index 0000000..bd374d5
--- /dev/null
+++ b/2016/aoc22/src/main.rs
@@ -0,0 +1,198 @@
+extern crate regex;
+
+use std::io::BufReader;
+use std::io::prelude::*;
+use std::fs::File;
+use std::collections::HashMap;
+use std::collections::HashSet;
+
+use regex::Regex;
+
+use std::str::FromStr;
+
+#[derive(Debug, Clone, Copy, Hash, PartialEq, Eq)]
+struct Node {
+    x: i8,
+    y: i8,
+    size: i16,
+    used: i16,
+    avail: i16,
+    blocker: bool
+}
+
+impl FromStr for Node {
+    type Err = String;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let reg = Regex::new(r"/dev/grid/node-x(\d+)-y(\d+) +(\d+)T +(\d+)T +(\d+)T +(\d+)%").unwrap();
+        let cap = match reg.captures(s) {
+            Some(cap) => cap,
+            None => return Err("Does not match regex".to_string())
+        };
+        Ok(Node {
+            x: cap.at(1).unwrap().parse().unwrap(),
+            y: cap.at(2).unwrap().parse().unwrap(),
+            size: cap.at(3).unwrap().parse().unwrap(),
+            used: cap.at(4).unwrap().parse().unwrap(),
+            avail: cap.at(5).unwrap().parse().unwrap(),
+            blocker: false
+        })
+    }
+}
+
+impl Node {
+    fn is_viable_pair(&self, other: &Node) -> bool {
+        (self.x != other.x || self.y != other.y) && self.used > 0 && self.used <= other.avail
+    }
+
+    fn recalculate_avail(&mut self) {
+        self.avail = self.size - self.used;
+        debug_assert!(self.avail >= 0);
+        debug_assert!(self.used >= 0);
+    }
+}
+
+#[derive(Clone, Hash, PartialEq, Eq)]
+struct Grid {
+    nodes: Vec<Vec<Node>>,
+    goal_x: i8,
+    goal_y: i8
+}
+
+impl Grid {
+    fn new(nodes: Vec<Node>) -> Grid {
+        let mut grid_nodes = Vec::new();
+        let mut next_col = Vec::new();
+
+        let mut current_x = 0;
+        
+        for node in nodes {
+            if current_x != node.x {
+                grid_nodes.push(next_col);
+                next_col = Vec::new();
+                current_x += 1;
+            }
+            
+            next_col.push(node);
+        }
+        grid_nodes.push(next_col);
+        grid_nodes = Grid::normalize(grid_nodes);
+
+        Grid {
+            nodes: grid_nodes,
+            goal_x: current_x,
+            goal_y: 0
+        }
+    }
+
+    fn normalize(mut nodes: Vec<Vec<Node>>) -> Vec<Vec<Node>> {
+        for x in 0..nodes.len() {
+            for y in 0..nodes[x].len() {
+                nodes[x][y].size = ((nodes[x][y].size + 50)/100) * 100;
+                nodes[x][y].used = ((nodes[x][y].used + 50)/100) * 100;
+                nodes[x][y].avail = ((nodes[x][y].avail + 50)/100) * 100;
+            }
+        }
+        nodes
+    }
+
+    fn is_final(&self) -> bool {
+        self.goal_x == 0 && self.goal_y == 0
+    }
+
+    fn make_move(&self, x: i8, y: i8, dx: i8, dy: i8) -> Option<Grid> {
+        if x+dx < 0 || x+dx >= self.nodes.len() as i8 || y+dy < 0 || y+dy >= self.nodes[x as usize].len() as i8 {
+            return None;
+        }
+        if !self.nodes[x as usize][y as usize].is_viable_pair(&self.nodes[(x+dx) as usize][(y+dy) as usize]) {
+            return None;
+        }
+
+        let mut new_grid = self.clone();
+        new_grid.nodes[(x+dx) as usize][(y+dy) as usize].used += new_grid.nodes[x as usize][y as usize].used;
+        new_grid.nodes[(x+dx) as usize][(y+dy) as usize].recalculate_avail();
+        new_grid.nodes[x as usize][y as usize].used = 0;
+        new_grid.nodes[x as usize][y as usize].recalculate_avail();
+        
+        if new_grid.goal_x == x && new_grid.goal_y == y {
+            new_grid.goal_x = x+dx;
+            new_grid.goal_y = y+dy;
+        }
+
+        Some(new_grid)
+    }
+    
+    fn available_moves(&self) -> Vec<Grid> {
+        let mut moves = Vec::with_capacity(4);
+        
+        for x in 0..self.nodes.len() as i8 {
+            for y in 0..self.nodes[x as usize].len() as i8 {
+                match self.make_move(x, y, -1, 0) {
+                    Some(grid) => { moves.push(grid); },
+                    None => {}
+                };
+                match self.make_move(x, y, 0, -1) {
+                    Some(grid) => { moves.push(grid); },
+                    None => {}
+                };
+                match self.make_move(x, y, 1, 0) {
+                    Some(grid) => { moves.push(grid); },
+                    None => {}
+                };
+                match self.make_move(x, y, 0, 1) {
+                    Some(grid) => { moves.push(grid); },
+                    None => {}
+                };
+            }
+        }
+
+        moves
+    }
+}
+
+
+fn main() {
+    let nodes = read_input();
+
+    let initial = Grid::new(nodes);
+    println!("Initial grid has {} possible moves", initial.available_moves().len());
+    
+    let mut explored: HashSet<Grid> = HashSet::new();
+    let mut frontier: HashMap<Grid, u32> = HashMap::new();
+    frontier.insert(initial, 0);
+    let mut found_final = false;
+
+    while !found_final {
+        let (best_frontier, moves) = find_best_frontiers(&frontier);
+        
+        let new_states = best_frontier.available_moves();
+        found_final = new_states.iter().any(|ref s| s.is_final());
+
+        for state in new_states {
+            if !(explored.contains(&state) || frontier.contains_key(&state)) {
+                frontier.insert(state, moves+1);
+            }
+        }
+        
+        frontier.remove(&best_frontier);
+        explored.insert(best_frontier);
+    }
+
+    let (final_frontier, moves) = frontier.iter().find(|&(s, _)| s.is_final()).unwrap();
+    println!("It took {} moves to get the data", moves);
+}
+
+fn read_input() -> Vec<Node> {
+    let file = BufReader::new(File::open("input.txt").unwrap());
+
+    file.lines()
+        .skip(2)
+        .filter_map(|line| Node::from_str(line.unwrap().as_ref()).ok())
+        .collect()
+}
+
+fn find_best_frontiers(frontier: &HashMap<Grid, u32>) -> (Grid, u32) {
+    frontier.iter().min_by_key(|&(ref grid, &moves)| {
+        grid.goal_x as u32 + grid.goal_y as u32 + moves
+    }).map(|(&ref grid, &moves)| (grid.clone(), moves.clone())).unwrap()
+}