diff --git a/lib/dijkstra/src/lib.rs b/lib/dijkstra/src/lib.rs
index fce79a4..7dd66f7 100644
--- a/lib/dijkstra/src/lib.rs
+++ b/lib/dijkstra/src/lib.rs
@@ -23,7 +23,7 @@ impl<T> Debug for dyn Matrix<T> {
 }
 
 pub struct Dijkstra<'a, T> {
-    matrix: Box<&'a mut dyn Matrix<T>>,
+    matrix: &'a mut dyn Matrix<T>,
     unvisited_with_distance: HashSet<Coordinate>,
     unvisited_without_distance: HashSet<Coordinate>,
 }
@@ -40,9 +40,9 @@ impl<'a, T> Dijkstra<'a, T>
 where
     T: PartialOrd + Add<Output = T> + Display + Copy + Debug,
 {
-    pub fn new(matrix: Box<&'a mut dyn Matrix<T>>) -> Self {
+    pub fn new(matrix: &'a mut dyn Matrix<T>) -> Self {
         let unvisited_with_distance = HashSet::new();
-        let unvisited_without_distance = Self::initialize_unvisited_set(*matrix, START);
+        let unvisited_without_distance = Self::initialize_unvisited_set(&*matrix, START);
         Self {
             matrix,
             unvisited_with_distance,
diff --git a/src/euler81/src/main.rs b/src/euler81/src/main.rs
index d99d3a0..11bad4f 100644
--- a/src/euler81/src/main.rs
+++ b/src/euler81/src/main.rs
@@ -110,7 +110,7 @@ impl Matrix {
 
 fn main() {
     let mut matrix = Matrix::load(Path::new(FILENAME));
-    let mut dijkstra = Dijkstra::new(Box::new(&mut matrix));
+    let mut dijkstra = Dijkstra::new(&mut matrix);
     dijkstra.solve();
     let result = matrix
         .get((LENGTH - 1, LENGTH - 1))