diff --git a/.idea/encodings.xml b/.idea/encodings.xml
index 228e9f1..fcd3bfa 100644
--- a/.idea/encodings.xml
+++ b/.idea/encodings.xml
@@ -3,5 +3,7 @@
   <component name="Encoding">
     <file url="file://$PROJECT_DIR$/Lab3/src/main/java" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/Lab3/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/Lab4/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/Lab4/src/main/resources" charset="UTF-8" />
   </component>
 </project>
\ No newline at end of file
diff --git a/.idea/misc.xml b/.idea/misc.xml
index d56e9ca..c449b97 100644
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@@ -8,6 +8,7 @@
     <option name="originalFiles">
       <list>
         <option value="$PROJECT_DIR$/Lab3/pom.xml" />
+        <option value="$PROJECT_DIR$/Lab4/pom.xml" />
       </list>
     </option>
   </component>
diff --git a/Lab4/pom.xml b/Lab4/pom.xml
new file mode 100644
index 0000000..18cb798
--- /dev/null
+++ b/Lab4/pom.xml
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>org.lumijiez</groupId>
+    <artifactId>Lab4</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <properties>
+        <maven.compiler.source>17</maven.compiler.source>
+        <maven.compiler.target>17</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+
+</project>
\ No newline at end of file
diff --git a/Lab4/src/main/java/org/lumijiez/intf/LumiQueue.java b/Lab4/src/main/java/org/lumijiez/intf/LumiQueue.java
new file mode 100644
index 0000000..d5a94ef
--- /dev/null
+++ b/Lab4/src/main/java/org/lumijiez/intf/LumiQueue.java
@@ -0,0 +1,11 @@
+package org.lumijiez.intf;
+
+public interface LumiQueue<E> {
+    void enqueue(E item);
+    E dequeue();
+    E peek();
+    boolean isEmpty();
+    int size();
+    void clear();
+}
+
diff --git a/Lab4/src/main/java/org/lumijiez/intf/LumiStack.java b/Lab4/src/main/java/org/lumijiez/intf/LumiStack.java
new file mode 100644
index 0000000..2066fc3
--- /dev/null
+++ b/Lab4/src/main/java/org/lumijiez/intf/LumiStack.java
@@ -0,0 +1,11 @@
+package org.lumijiez.intf;
+
+public interface LumiStack<E> {
+
+    void push(E item);
+    E pop();
+    E peek();
+    boolean isEmpty();
+    int size();
+    void clear();
+}
diff --git a/Lab4/src/main/java/org/lumijiez/stacks/ArrayLumiStack.java b/Lab4/src/main/java/org/lumijiez/stacks/ArrayLumiStack.java
new file mode 100644
index 0000000..8971046
--- /dev/null
+++ b/Lab4/src/main/java/org/lumijiez/stacks/ArrayLumiStack.java
@@ -0,0 +1,65 @@
+package org.lumijiez.stacks;
+
+import org.lumijiez.intf.LumiStack;
+
+import java.util.EmptyStackException;
+
+public class ArrayLumiStack<E> implements LumiStack<E> {
+    private final int MAX_CAPACITY_DEFAULT = 10;
+    private Object[] array;
+    private int size;
+
+    public ArrayLumiStack() {
+        array = new Object[MAX_CAPACITY_DEFAULT];
+        size = 0;
+    }
+
+    public ArrayLumiStack(int capacity) {
+        array = new Object[capacity];
+        size = 0;
+    }
+
+    @Override
+    public void push(E item) {
+        if (size == array.length) {
+            throw new StackOverflowError("Stack is full");
+        }
+        array[size++] = item;
+    }
+
+    @Override
+    public E pop() {
+        if (isEmpty()) {
+            throw new EmptyStackException();
+        }
+        E item = (E) array[--size];
+        array[size] = null;
+        return item;
+    }
+
+    @Override
+    public E peek() {
+        if (isEmpty()) {
+            throw new EmptyStackException();
+        }
+        return (E) array[size - 1];
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return size == 0;
+    }
+
+    @Override
+    public int size() {
+        return size;
+    }
+
+    @Override
+    public void clear() {
+        for (int i = 0; i < size; i++) {
+            array[i] = null;
+        }
+        size = 0;
+    }
+}
diff --git a/Lab4/src/main/java/org/lumijiez/stacks/DynamicArrayLumiStack.java b/Lab4/src/main/java/org/lumijiez/stacks/DynamicArrayLumiStack.java
new file mode 100644
index 0000000..5a6f1e5
--- /dev/null
+++ b/Lab4/src/main/java/org/lumijiez/stacks/DynamicArrayLumiStack.java
@@ -0,0 +1,65 @@
+package org.lumijiez.stacks;
+
+import org.lumijiez.intf.LumiStack;
+
+import java.util.EmptyStackException;
+
+public class DynamicArrayLumiStack<E> implements LumiStack<E> {
+    private Object[] array;
+    private int size;
+    private static final int DEFAULT_CAPACITY = 10;
+
+    public DynamicArrayLumiStack() {
+        array = new Object[DEFAULT_CAPACITY];
+        size = 0;
+    }
+
+    @Override
+    public void push(E item) {
+        ensureCapacity(size + 1);
+        array[size++] = item;
+    }
+
+    @Override
+    public E pop() {
+        if (isEmpty()) {
+            throw new EmptyStackException();
+        }
+        E item = (E) array[--size];
+        array[size] = null;
+        return item;
+    }
+
+    @Override
+    public E peek() {
+        if (isEmpty()) {
+            throw new EmptyStackException();
+        }
+        return (E) array[size - 1];
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return size == 0;
+    }
+
+    @Override
+    public int size() {
+        return size;
+    }
+
+    @Override
+    public void clear() {
+        for (int i = 0; i < size; i++) {
+            array[i] = null;
+        }
+        size = 0;
+    }
+
+    private void ensureCapacity(int minCapacity) {
+        if (minCapacity > array.length) {
+            int newCapacity = Math.max(array.length * 2, minCapacity);
+            array = java.util.Arrays.copyOf(array, newCapacity);
+        }
+    }
+}
diff --git a/Lab4/src/main/java/org/lumijiez/stacks/LinkedListLumiStack.java b/Lab4/src/main/java/org/lumijiez/stacks/LinkedListLumiStack.java
new file mode 100644
index 0000000..b571bc5
--- /dev/null
+++ b/Lab4/src/main/java/org/lumijiez/stacks/LinkedListLumiStack.java
@@ -0,0 +1,46 @@
+package org.lumijiez.stacks;
+
+import org.lumijiez.intf.LumiStack;
+
+import java.util.EmptyStackException;
+import java.util.LinkedList;
+
+public class LinkedListLumiStack<E> implements LumiStack<E> {
+    private LinkedList<E> list = new LinkedList<>();
+
+    @Override
+    public void push(E item) {
+        list.addFirst(item);
+    }
+
+    @Override
+    public E pop() {
+        if (isEmpty()) {
+            throw new EmptyStackException();
+        }
+        return list.removeFirst();
+    }
+
+    @Override
+    public E peek() {
+        if (isEmpty()) {
+            throw new EmptyStackException();
+        }
+        return list.getFirst();
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return list.isEmpty();
+    }
+
+    @Override
+    public int size() {
+        return list.size();
+    }
+
+    @Override
+    public void clear() {
+        list.clear();
+    }
+}