diff --git a/src/Day04.java b/src/Day04.java
new file mode 100644
index 0000000..af80257
--- /dev/null
+++ b/src/Day04.java
@@ -0,0 +1,138 @@
+package src;
+
+import java.io.FileReader;
+import java.time.Duration;
+import java.time.Instant;
+import java.util.List;
+import java.util.Map;
+import java.util.Scanner;
+
+public class Day04 {
+
+    private static int neighbors = 0;
+    private static int score = 0;
+    private static int round = 0;
+    private static Map<String, Boolean> floor = new java.util.HashMap<>();
+
+    public static void main(String[] args) {
+        Instant start = Instant.now();
+        part1();
+        Instant middle = Instant.now();
+        part2();
+        Instant end = Instant.now();
+        IO.println("part 1: " + Duration.between(start, middle).toMillis() + " ms");
+        IO.println("part 2: " + Duration.between(middle, end).toMillis() + " ms");
+    }
+
+    private static void part1() {
+        try (Scanner scanner = new Scanner(new FileReader("resources/inputs/04/input"))) {
+            floor = new java.util.HashMap<>();
+
+            int rowIndex = 0;
+            int size = 0;
+            score = 0;
+            while (scanner.hasNextLine()) {
+                String[] row = scanner.nextLine().split("");
+                size = row.length;
+                for (int i = 0; i < size; i++) {
+                    String key = "%s-%s".formatted(i, rowIndex);
+                    if (row[i].equals("@")) {
+                        floor.put(key, true);
+                    } else {
+                        floor.put(key, false);
+                    }
+
+                }
+                rowIndex++;
+            }
+            floor.forEach((key, value) -> {
+                if (value) {
+                    String[] coords = key.split("-");
+                    int x = Integer.parseInt(coords[0]);
+                    int y = Integer.parseInt(coords[1]);
+                    neighbors = 0;
+                    List.of(
+                            "%s-%s".formatted(x - 1, y),
+                            "%s-%s".formatted(x + 1, y),
+                            "%s-%s".formatted(x, y - 1),
+                            "%s-%s".formatted(x, y + 1),
+                            "%s-%s".formatted(x + 1, y - 1),
+                            "%s-%s".formatted(x - 1, y - 1),
+                            "%s-%s".formatted(x + 1, y + 1),
+                            "%s-%s".formatted(x - 1, y + 1)).forEach((coord) -> {
+                                if (floor.getOrDefault(coord, false)) {
+                                    neighbors += 1;
+                                }
+                            });
+                    if (neighbors < 4) {
+                        score += 1;
+                    }
+                }
+            });
+            IO.println(score);
+        } catch (Exception e) {
+            IO.println(e.getMessage());
+        }
+    }
+
+    private static void part2() {
+        try (Scanner scanner = new Scanner(new FileReader("resources/inputs/04/input"))) {
+            floor = new java.util.HashMap<>();
+            int rowIndex = 0;
+            int size = 0;
+            score = 0;
+            while (scanner.hasNextLine()) {
+                String[] row = scanner.nextLine().split("");
+                size = row.length;
+                for (int i = 0; i < size; i++) {
+                    String key = "%s-%s".formatted(i, rowIndex);
+                    if (row[i].equals("@")) {
+                        floor.put(key, true);
+                    } else {
+                        floor.put(key, false);
+                    }
+
+                }
+                rowIndex++;
+            }
+            while (true) {
+                Map<String, Boolean> newFloor = new java.util.HashMap<>(floor);
+                floor.forEach((key, value) -> {
+                    if (value) {
+                        String[] coords = key.split("-");
+                        int x = Integer.parseInt(coords[0]);
+                        int y = Integer.parseInt(coords[1]);
+                        neighbors = 0;
+                        List.of(
+                                "%s-%s".formatted(x - 1, y),
+                                "%s-%s".formatted(x + 1, y),
+                                "%s-%s".formatted(x, y - 1),
+                                "%s-%s".formatted(x, y + 1),
+                                "%s-%s".formatted(x + 1, y - 1),
+                                "%s-%s".formatted(x - 1, y - 1),
+                                "%s-%s".formatted(x + 1, y + 1),
+                                "%s-%s".formatted(x - 1, y + 1)).forEach((coord) -> {
+                                    if (floor.getOrDefault(coord, false)) {
+                                        neighbors += 1;
+                                    }
+                                });
+                        if (neighbors < 4) {
+                            round += 1;
+                            newFloor.put(key, false);
+                        }
+                    }
+                });
+                floor = newFloor;
+                if (round == 0) {
+                    break;
+                } else {
+                    score = score + round;
+                    round = 0;
+                }
+            }
+            IO.println(score);
+        } catch (Exception e) {
+            IO.println(e.getMessage());
+        }
+    }
+}