diff --git a/group12/441908378/ArrayList.java b/group12/441908378/ArrayList.java
new file mode 100755
index 0000000000..45e495867c
--- /dev/null
+++ b/group12/441908378/ArrayList.java
@@ -0,0 +1,50 @@
+import java.util.Arrays;
+
+public class ArrayList  {
+
+private int size = 0;
+
+private Object[] elementData = new Object[100];
+
+public void enlargeCapacity(int minCapacity){
+	int oldCapacity=elementData.length;
+	if(oldCapacity<minCapacity){
+		oldCapacity=(oldCapacity*3)/2+1;
+	}
+}
+
+public void add(Object o){
+ 	enlargeCapacity(elementData.length+1);
+ 	elementData[elementData.length+1]=o;
+}
+public void add(int index, Object o){
+	enlargeCapacity(elementData.length+1);
+	Object data[]= Arrays.copyOfRange(elementData, index, elementData.length);
+	elementData[index] = o;
+	System.arraycopy(data, 0, elementData, index+1, elementData.length);
+	
+}
+
+public Object get(int index){
+	Object o;
+	o=elementData[index];
+	return o;
+}
+
+public Object remove(int index){
+	Object o;
+	o=elementData[index];
+	Object data[]= Arrays.copyOfRange(elementData, index+1, elementData.length);
+	System.arraycopy(data, 0, elementData, index, elementData.length);
+	return o;
+}
+
+public int size(){
+ return size;
+}
+
+//public Iterator iterator(){
+//return null;
+//}
+
+}
diff --git a/group12/441908378/BinaryTreeNode.java b/group12/441908378/BinaryTreeNode.java
new file mode 100755
index 0000000000..972af1eec6
--- /dev/null
+++ b/group12/441908378/BinaryTreeNode.java
@@ -0,0 +1,47 @@
+
+public class BinaryTreeNode {
+
+	private Object data;
+	private BinaryTreeNode left;
+	private BinaryTreeNode right;
+	
+	public Object getData() {
+		return data;
+	}
+	public void setData(Object data) {
+		this.data = data;
+	}
+	public BinaryTreeNode getLeft() {
+		return left;
+	}
+	public void setLeft(BinaryTreeNode left) {
+		this.left = left;
+	}
+	public BinaryTreeNode getRight() {
+		return right;
+	}
+	public void setRight(BinaryTreeNode right) {
+		this.right = right;
+	}
+	
+	public BinaryTreeNode insert(Object o){
+		BinaryTreeNode node;
+		do{
+			node=compare(o);
+		}while(node==null);
+		node.data=o;
+		return  node;
+	}
+	
+	public BinaryTreeNode compare(Object o){
+		int a=(Integer)data;
+		int b=(Integer)o;
+		if(a>b){
+			return left;
+		}else{
+			return right;
+		}
+	}
+	
+
+}
diff --git a/group12/441908378/LinkedList.java b/group12/441908378/LinkedList.java
new file mode 100755
index 0000000000..0d0339bc01
--- /dev/null
+++ b/group12/441908378/LinkedList.java
@@ -0,0 +1,121 @@
+public class LinkedList  {
+
+private Node head;
+
+private static  class Node{
+	Object data;
+	Node next;
+}
+
+public boolean hasNext(Node a){
+	if(a.next!=null){
+		return true;
+	}
+	return false;
+}
+
+public Node getIndex(int index){
+	Node a=head.next;
+	for(int i=0;i<index;i++){
+		a=a.next;
+	}
+	return a;
+}
+
+public void add(Object o){
+	Node a;
+	if(!hasNext(head)){
+		a=head.next;
+		a.data=o;
+		}else{
+			a=head.next;
+			while(a.next!=null){
+				a=a.next;
+			}
+			a=a.next;
+			a.data=o;
+		}
+}
+
+
+public void add(int index , Object o){
+	Node a=getIndex(index);
+	Node b=null;
+	b.data=o;
+	b.next=a.next;
+	a.next=b;	
+}
+public Object get(int index){
+	Object o;
+	Node a=getIndex(index);
+	o=a.data;
+	return o;
+}
+public Object remove(int index){
+	Node a=getIndex(index-1);
+	Node b=a.next;
+	Object c=b.data;
+	a.next=b.next;
+	b.next=null;
+	return c;
+}
+
+public int size(){
+	Node a=head.next;
+	int i=0;
+	while(a.next==null){
+		a=a.next;
+		i++;
+	}
+	return i;
+}
+
+public void addFirst(Object o){
+	Node a=null;
+	a.data=o;
+	Node b=head.next;
+	a.next=b;
+	head.next=a;
+}
+public void addLast(Object o){
+	Node a;
+	if(!hasNext(head)){
+		a=head.next;
+		a.data=o;
+		}else{
+			a=head.next;
+			while(a.next!=null){
+				a=a.next;
+			}
+			a=a.next;
+			a.data=o;
+		}
+}
+public Object removeFirst(){
+	Node a=head.next;
+	Node b=a.next;
+	Object c=a.data;
+	head.next=b;
+	a.next=null;
+	return c;
+}
+public Object removeLast(){
+	Node a=head.next;
+	while(a.next.next!=null){
+		a=a.next;
+	};
+	Object b=a.next.data;
+	a.next=null;
+	return b;
+	
+}
+
+
+//public Iterator iterator(){
+//return null;
+//}
+
+
+
+
+}
diff --git a/group12/441908378/Queue.java b/group12/441908378/Queue.java
new file mode 100755
index 0000000000..1485b891a6
--- /dev/null
+++ b/group12/441908378/Queue.java
@@ -0,0 +1,39 @@
+import java.util.Arrays;
+
+
+public class Queue {
+
+	
+	private int size = 0;
+
+	private Object[] elementData = new Object[100];
+	
+	public void enlargeCapacity(int minCapacity){
+		int oldCapacity=elementData.length;
+		if(oldCapacity<minCapacity){
+			oldCapacity=(oldCapacity*3)/2+1;
+		}
+	}
+	
+	public void enQueue(Object o){		
+		enlargeCapacity(elementData.length+1);
+	 	elementData[elementData.length+1]=o;
+	}
+	
+	public Object deQueue(){
+		Object a = elementData[0];
+		elementData=Arrays.copyOfRange(elementData, 1, elementData.length);
+		return null;
+	}
+	
+	public boolean isEmpty(){
+		if(elementData.length==0){
+		return true;
+		}
+		return false;
+	}
+	
+	public int size(){
+		return elementData.length;
+	}
+}
diff --git a/group12/441908378/Stack.java b/group12/441908378/Stack.java
new file mode 100755
index 0000000000..acfec33cd1
--- /dev/null
+++ b/group12/441908378/Stack.java
@@ -0,0 +1,30 @@
+
+public class Stack {
+	private ArrayList elementData = new ArrayList();
+
+	private int size = 0;
+
+	public void push(Object o){		
+	elementData.add(o);
+	}
+	
+	public Object pop(){
+		Object o=elementData.get(elementData.size());
+		elementData.remove(elementData.size());
+		return o;
+	}
+	
+	public Object peek(){
+		Object o=elementData.get(elementData.size());
+		return o;
+	}
+	public boolean isEmpty(){
+		if(elementData.size()==0){
+			return true;
+		}
+		return false;
+	}
+	public int size(){
+		return elementData.size();
+	}
+}