3 files changed, 57 insertions, 21 deletions

diff --git a/src/ch/epfl/maze/physical/Daedalus.java b/src/ch/epfl/maze/physical/Daedalus.java
index 4670064..0179156 100644
--- a/src/ch/epfl/maze/physical/Daedalus.java
+++ b/src/ch/epfl/maze/physical/Daedalus.java
@@ -1,7 +1,9 @@
 package ch.epfl.maze.physical;
 
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
@@ -14,11 +16,11 @@ import java.util.stream.Stream;
  */
 public final class Daedalus extends World {
 
-    private final List<Predator> predators;
-    private final List<Predator> predatorHistory;
+    private final Set<Predator> predators;
+    private final Set<Predator> predatorHistory;
 
-    private final List<Prey> preys;
-    private final List<Prey> preyHistory;
+    private final Set<Prey> preys;
+    private final Set<Prey> preyHistory;
 
     /**
      * Constructs a Daedalus with a labyrinth structure
@@ -28,11 +30,11 @@ public final class Daedalus extends World {
     public Daedalus(int[][] labyrinth) {
         super(labyrinth);
 
-        this.predators = new ArrayList<>();
-        this.predatorHistory = new ArrayList<>();
+        this.predators = new HashSet<>();
+        this.predatorHistory = new HashSet<>();
 
-        this.preys = new ArrayList<>();
-        this.preyHistory = new ArrayList<>();
+        this.preys = new HashSet<>();
+        this.preyHistory = new HashSet<>();
     }
 
     @Override
@@ -79,28 +81,48 @@ public final class Daedalus extends World {
     }
 
     @Override
-    public List<Animal> getAnimals() {
+    public Set<Animal> getAnimalSet() {
         return Stream
                 .concat(this.predators.stream(), this.preys.stream())
-                .collect(Collectors.toList());
+                .collect(Collectors.toSet());
+    }
+
+    /**
+     * Returns a copy of the set of all current predators in the daedalus.
+     *
+     * @return A set of all predators in the daedalus
+     */
+    public Set<Predator> getPredatorSet() {
+        return new HashSet<>(this.predators);
     }
 
     /**
      * Returns a copy of the list of all current predators in the daedalus.
      *
      * @return A list of all predators in the daedalus
+     * @deprecated Use @code{Set<Predator> getPredatorSet()} instead
      */
     public List<Predator> getPredators() {
-        return this.predators;
+        return new ArrayList<>(this.getPredatorSet());
+    }
+
+    /**
+     * Returns a copy of the set of all current preys in the daedalus.
+     *
+     * @return A set of all preys in the daedalus
+     */
+    public Set<Prey> getPreySet() {
+        return new HashSet<>(this.preys);
     }
 
     /**
      * Returns a copy of the list of all current preys in the daedalus.
      *
      * @return A list of all preys in the daedalus
+     * @deprecated Use @code{Set<Prey> getPreySet()} instead
      */
     public List<Prey> getPreys() {
-        return this.preys;
+        return new ArrayList<>(this.getPreySet());
     }
 
     /**
diff --git a/src/ch/epfl/maze/physical/Maze.java b/src/ch/epfl/maze/physical/Maze.java
index d3ba645..d3273c8 100644
--- a/src/ch/epfl/maze/physical/Maze.java
+++ b/src/ch/epfl/maze/physical/Maze.java
@@ -1,7 +1,7 @@
 package ch.epfl.maze.physical;
 
-import java.util.ArrayList;
-import java.util.List;
+import java.util.HashSet;
+import java.util.Set;
 
 /**
  * Maze in which an animal starts from a starting point and must find the exit.
@@ -13,8 +13,8 @@ import java.util.List;
  */
 public final class Maze extends World {
 
-    private final List<Animal> animals;
-    private final List<Animal> animalHistory;
+    private final Set<Animal> animals;
+    private final Set<Animal> animalHistory;
 
     /**
      * Constructs a Maze with a labyrinth structure.
@@ -24,8 +24,8 @@ public final class Maze extends World {
     public Maze(int[][] labyrinth) {
         super(labyrinth);
 
-        this.animals = new ArrayList<>();
-        this.animalHistory = new ArrayList<>();
+        this.animals = new HashSet<>();
+        this.animalHistory = new HashSet<>();
     }
 
     @Override
@@ -34,8 +34,8 @@ public final class Maze extends World {
     }
 
     @Override
-    public List<Animal> getAnimals() {
-        return this.animals;
+    public Set<Animal> getAnimalSet() {
+        return new HashSet<>(this.animals);
     }
 
     /**
diff --git a/src/ch/epfl/maze/physical/World.java b/src/ch/epfl/maze/physical/World.java
index 7d33472..9730876 100644
--- a/src/ch/epfl/maze/physical/World.java
+++ b/src/ch/epfl/maze/physical/World.java
@@ -5,6 +5,7 @@ import ch.epfl.maze.util.Vector2D;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Set;
 
 /**
  * World that is represented by a labyrinth of tiles in which an {@code Animal}
@@ -70,11 +71,24 @@ public abstract class World {
     abstract public void reset();
 
     /**
+     * Returns a copy of the set of all current animals in the world.
+     *
+     * @return A set of all animals in the world
+     */
+    public Set<Animal> getAnimalSet() {
+        return null;
+    }
+
+    /**
      * Returns a copy of the list of all current animals in the world.
      *
      * @return A list of all animals in the world
+     * @implNote Not abstract for compatibility purpose (in order not to break tests)
+     * @deprecated Use getAnimalSet() instead
      */
-    abstract public List<Animal> getAnimals();
+    public List<Animal> getAnimals() {
+        return new ArrayList<>(this.getAnimalSet());
+    }
 
     /**
      * Checks in a safe way the tile number at position (x, y) in the labyrinth.