diff --git a/rust18/Cargo.lock b/rust18/Cargo.lock
new file mode 100644
index 0000000..ccd8da2
--- /dev/null
+++ b/rust18/Cargo.lock
@@ -0,0 +1,5 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "rust18"
+version = "0.1.0"
diff --git a/rust18/input.txt b/rust18/input.txt
new file mode 100644
index 0000000..ba97e4d
--- /dev/null
+++ b/rust18/input.txt
@@ -0,0 +1,81 @@
+#################################################################################
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\ No newline at end of file
diff --git a/rust18/src/main.rs b/rust18/src/main.rs
index e7a11a9..95db40e 100644
--- a/rust18/src/main.rs
+++ b/rust18/src/main.rs
@@ -1,3 +1,213 @@
-fn main() {
-    println!("Hello, world!");
+use std::env;
+use std::fs;
+use std::error::Error;
+use std::collections::{BTreeMap, BTreeSet, VecDeque, HashMap};
+#[derive(Debug)]
+struct Vm {
+    a: Vec<i64>,
+    i: usize,
+    relbase: usize,
+    halt: bool,
+}
+
+fn distances_accessible(board: &Vec<Vec<char>>, x: usize, y: usize, has_keys: &BTreeSet<char>) -> Vec<(char, (usize, usize), i64)> {
+    let sides: Vec<(i64, i64)> = vec![(0,-1),(1,0),(0,1),(-1,0)];
+    let mut queue = VecDeque::new();
+    let mut dist = BTreeMap::new();
+    dist.insert((x,y),0i64);
+    queue.push_back((x,y));
+    let mut res = vec![];
+    while queue.len() > 0 {
+        let (x, y) = queue.pop_front().unwrap();
+        let d = dist[&(x, y)]+1;
+        for (dx,dy) in &sides {
+            let xx = (x as i64 + dx) as usize;
+            let yy = (y as i64 + dy) as usize;
+            if !dist.contains_key(&(xx, yy)) {
+                let c = board[yy][xx];
+                if c == '.' || c == '@' || (c>='a' && c <='z') || (c>='A' && c <= 'Z' && has_keys.contains(&c.to_ascii_lowercase())) {
+                    dist.insert((xx, yy), d);
+                    if  c>='a' && c <='z' && !has_keys.contains(&c) {
+                        res.push((c, (xx,yy), d));
+                    } else {
+                        queue.push_back((xx, yy));
+                    }
+                }
+            }
+        }
+    }
+    // dbg!(&res);
+    res
+}
+
+fn distances_letters(board: &Vec<Vec<char>>, x: usize, y: usize) -> Vec<(char, i64)> {
+    let sides: Vec<(i64, i64)> = vec![(0,-1),(1,0),(0,1),(-1,0)];
+    let mut queue = VecDeque::new();
+    let mut dist = BTreeMap::new();
+    dist.insert((x,y),0i64);
+    queue.push_back((x,y));
+    let mut res = vec![];
+    while queue.len() > 0 {
+        let (x, y) = queue.pop_front().unwrap();
+        for (dx,dy) in &sides {
+            let xx = (x as i64 + dx) as usize;
+            let yy = (y as i64 + dy) as usize;
+            if !dist.contains_key(&(xx, yy)) {
+                let c = board[yy][xx];
+                if c != '#' {
+                    let d = dist[&(x, y)]+1;
+                    dist.insert((xx, yy), d);
+                    if (c>='a' && c <='z') || (c>='A' && c <='Z') {
+                        res.push((c, d));
+                    }
+                    if !(c>='A' && c <='Z') {
+                        queue.push_back((xx, yy));
+                    }
+                }
+            }
+        }
+    }
+    // dbg!(&res);
+    res
+}
+
+fn solve(board: &Vec<Vec<char>>, x: usize, y: usize, has_keys: &mut BTreeSet<char>, all_keys_num: usize, key_order: &mut Vec<char>,
+    current_steps: i64, cache: &mut BTreeMap<(usize, usize, BTreeSet<char>), Vec<(char, (usize, usize), i64)>>,
+    cache2: &mut BTreeMap<(usize, usize, BTreeSet<char>), i64>,
+) -> i64 {
+    if let Some(solution) = cache2.get(&(x, y, has_keys.clone())) {
+        return current_steps + *solution;
+    }
+    let mut best_solution = 99999999;
+    let dists =
+        cache.entry((x, y, has_keys.clone())).or_insert_with(||distances_accessible(&board, x, y, &has_keys)).clone();
+    // dists.sort_by_key(|(c, xy, d)|*d);
+    // dbg!(&dists);
+    for (key, (xx,yy), d) in dists.iter() {
+        key_order.push(*key);
+        let solution = if key_order.len() == all_keys_num {
+            d + current_steps
+        } else {
+            has_keys.insert(*key);
+            let res = solve(&board, *xx, *yy, has_keys, all_keys_num, key_order, current_steps+d, cache, cache2);
+            has_keys.remove(key);
+            res
+        };
+        if best_solution > solution {
+            best_solution = solution;
+            // dbg!(has_keys.len());
+            // dbg!(best_solution);
+            // dbg!(cache.len());
+            // let mut s = String::new();
+            // for c in key_order.iter() {
+            //     s.push(*c);
+            // }
+            // println!("{}", s);
+        }
+        key_order.pop();
+    }
+    cache2.insert((x, y, has_keys.clone()), best_solution-current_steps);
+    best_solution
+}
+
+
+fn solve2(all_distances: &BTreeMap<char, Vec<(char, i64)>>, orig_mark: char, has_keys: &mut BTreeSet<char>, all_keys_num: usize,
+    visited_marks: &mut Vec<char>, current_steps: i64, prev_best_solution: i64, cache: &mut BTreeMap<(char, BTreeSet<char>), Vec<(char, i64)>>,
+) -> i64 {
+    let mut best_solution = prev_best_solution;
+
+    let ckey = (orig_mark, has_keys.clone());
+    let dists = cache.entry(ckey).or_insert_with(||{
+        let mut accessible_keys = BTreeMap::new();
+        let mut doors = BTreeSet::new();
+        let mut queue = VecDeque::new();
+        queue.push_back((orig_mark, 0));
+        while !queue.is_empty() {
+            let (m0, d0) = queue.pop_front().unwrap();
+            if current_steps + d0 > best_solution {
+                break;
+            }
+
+            for (m,d) in &all_distances[&m0] {
+                if *m>='a' && *m <='z' && !has_keys.contains(m) {
+                    if *accessible_keys.get(m).unwrap_or(&9999999) > d+d0 {
+                        accessible_keys.insert(*m, d+d0);
+                    }
+                } else {
+                    if has_keys.contains(&m.to_ascii_lowercase()) {
+                        if !doors.contains(m) {
+                            queue.push_back((*m, d0+d));
+                        }
+                    }
+                    doors.insert(m);
+                }
+            }
+        }
+        let mut dists: Vec<(char, i64)> = accessible_keys.into_iter().collect();
+        dists.sort_by_key(|(c, d)|*d);
+        return dists
+    }).clone();
+    for (key, d) in dists.iter() {
+        if current_steps + d > best_solution {
+            break;
+        }
+        visited_marks.push(*key);
+        let solution = if has_keys.len() == all_keys_num {
+            d + current_steps
+        } else {
+            solve2(all_distances, *key, has_keys, all_keys_num, visited_marks, current_steps+d, best_solution, cache)
+        };
+        if best_solution > solution {
+            best_solution = solution;
+            dbg!(has_keys.len());
+            dbg!(best_solution);
+            let mut s = String::new();
+            for c in visited_marks.iter() {
+                s.push(*c);
+            }
+            println!("{}", s);
+        }
+        has_keys.remove(key);
+        visited_marks.pop();
+    }
+    best_solution
+}
+
+fn main() -> Result<(), Box<dyn Error>> {
+    let task_part = &env::args().collect::<Vec<String>>()[1];
+    let input = fs::read_to_string("input.txt")?;
+
+    let board: Vec<Vec<char>> = input.lines().map(|l|l.chars().collect()).collect();
+
+    let mut x = 0;
+    let mut y = 0;
+    let mut all_keys = BTreeSet::new();
+    let mut all_distances: BTreeMap<char, Vec<(char, i64)>> = BTreeMap::new();
+
+    for (yy, row) in board.iter().enumerate() {
+        for (xx, c) in row.iter().enumerate() {
+            if *c == '@' {
+                x = xx;
+                y = yy;
+                // all_distances.insert(*c, distances_letters(&board, xx, yy));
+            }
+            if *c>='a' && *c <='z' {
+                all_keys.insert(*c);
+                // all_distances.insert(*c, distances_letters(&board, xx, yy));
+            }
+            if *c>='A' && *c <='Z' {
+                // all_distances.insert(*c, distances_letters(&board, xx, yy));
+            }
+        }
+    }
+
+    let mut has_keys = BTreeSet::new();
+    let mut visited_marks = vec![];
+    let mut cache = BTreeMap::new();
+    let mut cache2 = BTreeMap::new();
+    dbg!(solve(&board, x, y, &mut has_keys, all_keys.len(), &mut visited_marks, 0, &mut cache, &mut cache2));
+    dbg!(cache.len());
+    dbg!(cache2.len());
+
+    Ok(())
 }