diff --git a/group20/331798361/assignment1/src/com/coding/basic/ArrayList.java b/group20/331798361/assignment1/src/com/coding/basic/ArrayList.java
new file mode 100644
index 0000000000..0d960ee3d8
--- /dev/null
+++ b/group20/331798361/assignment1/src/com/coding/basic/ArrayList.java
@@ -0,0 +1,122 @@
+package com.coding.basic;
+
+import java.util.Arrays;
+
+public class ArrayList implements List {
+
+	
+	private int size = 0;
+	
+	private Object[] elementData = new Object[100];
+	
+	public void add(Object o){
+		int n = elementData.length;
+		int i = 0;
+		while (elementData[i] != null) {
+			i++;
+		}
+		if (i < n) {
+			elementData[i] = o;
+		} else {
+			Object[] temp = Arrays.copyOf(elementData, n + 1);
+			temp[n] = o;
+			elementData = temp;
+		}
+		size++;
+	}
+	public void add(int index, Object o){
+		int n = elementData.length;
+		int i = 0;
+		while (elementData[i] != null) {
+			i++;
+		}
+		if (index < 0 || index > i) {
+			System.out.println(index + " is invalid index!");
+			return;
+		}
+		if (i < n) {
+			for (int j = i; j > index; j--) {
+				elementData[j] = elementData[j - 1];
+			}
+			elementData[index] = o;
+		} else {
+			Object[] temp = Arrays.copyOf(elementData, n + 1);
+			for (int j = i; j > index; j--) {
+				temp[j] = temp[j - 1];
+			}
+			temp[index] = o;
+			elementData = temp;
+		}
+		size++;
+	}
+	
+	public Object get(int index){
+		int i = 0;
+		while (elementData[i] != null) {
+			i++;
+		}
+		if (index < 0 || index >= i) {
+			System.out.println(index + " is invalid index!");
+			return null;
+		} else {
+			return elementData[index];
+		}
+	}
+	
+	public Object remove(int index){
+		int i = 0;
+		while (elementData[i] != null) {
+			i++;
+		}
+		if (index < 0 || index >= i) {
+			System.out.println(index + " is invalid index!");
+			return null;
+		}
+		Object result = elementData[index];
+		for (int j = index; j < i; j++) {
+			elementData[j] = elementData[j + 1];
+		}
+		size--;
+		return result;
+	}
+	
+	public int size(){
+		return size;
+	}
+
+	public String toString() {
+		int i = 0;
+		while (elementData[i] != null) {
+			i++;
+		}
+		String result = "";
+		for (int j = 0; j < i - 1; j++) {
+			result += elementData[j].toString() + ", ";
+		}
+		result += elementData[size - 1].toString();
+		return result;
+	}
+	
+	public Iterator iterator(){
+		return null;
+	}
+
+	public static void main(String args[]){
+		ArrayList list1 = new ArrayList();
+		list1.add("a");
+		list1.add("b");
+		list1.add("c");
+		System.out.println(list1.toString());
+		list1.add(5, "d");
+		list1.add(1, "d");
+		System.out.println(list1.toString());
+		list1.add(4, "e");
+		System.out.println(list1.toString());
+		list1.get(5);
+		System.out.println(list1.get(0));
+		list1.remove(2);
+		System.out.println(list1.toString());
+		System.out.println(list1.size());
+	}
+	
+}
diff --git a/group20/331798361/assignment1/src/com/coding/basic/BinaryTreeNode.java b/group20/331798361/assignment1/src/com/coding/basic/BinaryTreeNode.java
new file mode 100644
index 0000000000..266eff3d56
--- /dev/null
+++ b/group20/331798361/assignment1/src/com/coding/basic/BinaryTreeNode.java
@@ -0,0 +1,32 @@
+package com.coding.basic;
+
+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){
+		return  null;
+	}
+	
+}
diff --git a/group20/331798361/assignment1/src/com/coding/basic/Iterator.java b/group20/331798361/assignment1/src/com/coding/basic/Iterator.java
new file mode 100644
index 0000000000..dbe8b9afb2
--- /dev/null
+++ b/group20/331798361/assignment1/src/com/coding/basic/Iterator.java
@@ -0,0 +1,7 @@
+package com.coding.basic;
+
+public interface Iterator {
+	public boolean hasNext();
+	public Object next();
+
+}
diff --git a/group20/331798361/assignment1/src/com/coding/basic/LinkedList.java b/group20/331798361/assignment1/src/com/coding/basic/LinkedList.java
new file mode 100644
index 0000000000..e029beaeb4
--- /dev/null
+++ b/group20/331798361/assignment1/src/com/coding/basic/LinkedList.java
@@ -0,0 +1,148 @@
+package com.coding.basic;
+
+public class LinkedList implements List {
+	
+	private Node head;
+	private int size;
+	
+	public void add(Object o){
+		if (head.data == null) {
+			head.data = o;
+			head.next = null;
+			size++;
+			return;
+		}
+		Node node = new Node(o);
+		Node curr = head;
+		while (curr.next != null) {
+			curr = curr.next;
+		}
+		curr.next = node;
+		size++;
+	}
+	public void add(int index , Object o){
+
+		if (index < 0 || index > size) {
+			System.out.println(index + " is invalid index!");
+			return;
+		}
+		if (head.data == null) {
+			if (index == 0) {
+				head.data = o;
+				head.next = null;
+				size++;
+				return;
+			} else {
+				System.out.println("invalid index!");
+				return;
+			}
+		}
+		Node node = new Node(o);
+		Node curr = head;
+		for (int i = 0; i < index - 1; i++) {
+			curr = curr.next;
+		}
+		Node temp = curr.next;
+		curr.next = node;
+		node.next = temp;
+		size++;
+	}
+	public Object get(int index){
+		if (index < 0 || index > size) {
+			System.out.println(index + " is invalid index!");
+			return null;
+		}
+		Node result = head;
+		for (int i = 0; i < index; i++) {
+			result = result.next;
+		}
+		return result;
+	}
+	public Object remove(int index){
+		if (index < 0 || index > size) {
+			System.out.println(index + " is invalid index!");
+			return null;
+		}
+		Node curr = head;
+		for (int i = 0; i < index - 1; i++) {
+			curr = curr.next;
+		}
+		Node result = curr.next;
+		curr.next = curr.next.next;
+		size--;
+		return result;
+	}
+	
+	public int size(){
+		return size;
+	}
+	
+	public void addFirst(Object o){
+		if (head.data == null) {
+			head.data = o;
+			head.next = null;
+			size++;
+			return;
+		}
+		Node temp = head;
+		head = new Node(o);
+		head.next = temp;
+		size++;
+	}
+
+	public void addLast(Object o){
+		if (head.data == null) {
+			head.data = o;
+			head.next = null;
+			size++;
+			return;
+		}
+		Node node = new Node(o);
+		Node curr = head;
+		while (curr.next != null) {
+			curr = curr.next;
+		}
+		curr.next = node;
+		size++;
+	}
+
+	public Object removeFirst(){
+		if (head.data == null) {
+			return null;
+		}
+		Node result = head;
+		head = head.next;
+		size--;
+		return result;
+	}
+
+	public Object removeLast(){
+		if (head.data == null) {
+			return null;
+		}
+		Node curr = head;
+		for (int i = 0; i < size - 1; i++) {
+			curr = curr.next;
+		}
+		Node result = curr.next;
+		curr.next = null;
+		size--;
+		return result;
+	}
+
+	public Iterator iterator(){
+		return null;
+	}
+	
+	
+	private static class Node{
+		Object data;
+		Node next;
+
+		Node(Object o) {
+			data = o;
+			next = null;
+		}
+		
+	}
+}
diff --git a/group20/331798361/assignment1/src/com/coding/basic/List.java b/group20/331798361/assignment1/src/com/coding/basic/List.java
new file mode 100644
index 0000000000..396b1f6416
--- /dev/null
+++ b/group20/331798361/assignment1/src/com/coding/basic/List.java
@@ -0,0 +1,9 @@
+package com.coding.basic;
+
+public interface List {
+	public void add(Object o);
+	public void add(int index, Object o);
+	public Object get(int index);
+	public Object remove(int index);
+	public int size();
+}
diff --git a/group20/331798361/assignment1/src/com/coding/basic/Queue.java b/group20/331798361/assignment1/src/com/coding/basic/Queue.java
new file mode 100644
index 0000000000..c4991a07f5
--- /dev/null
+++ b/group20/331798361/assignment1/src/com/coding/basic/Queue.java
@@ -0,0 +1,30 @@
+package com.coding.basic;
+
+
+public class Queue {
+	private LinkedList list = new LinkedList();
+
+	public void enQueue(Object o){
+		list.add(o);
+	}
+	
+	public Object deQueue(){
+		int length = list.size();
+		if (length == 0) {
+			return null;
+		}
+		return list.removeFirst();
+	}
+	
+	public boolean isEmpty(){
+		if (list.size() == 0) {
+			return true;
+		} else {
+			return false;
+		}
+	}
+	
+	public int size(){
+		return list.size();
+	}
+}
diff --git a/group20/331798361/assignment1/src/com/coding/basic/Stack.java b/group20/331798361/assignment1/src/com/coding/basic/Stack.java
new file mode 100644
index 0000000000..0a48545cea
--- /dev/null
+++ b/group20/331798361/assignment1/src/com/coding/basic/Stack.java
@@ -0,0 +1,37 @@
+package com.coding.basic;
+
+public class Stack {
+	private ArrayList elementData = new ArrayList();
+	
+	public void push(Object o) {
+		elementData.add(o);
+	}
+	
+	public Object pop(){
+		int length = elementData.size();
+		if (length == 0) {
+			return null;
+		}
+		return elementData.remove(length - 1);
+	}
+	
+	public Object peek(){
+		int length = elementData.size();
+		if (length == 0) {
+			return null;
+		}
+		return elementData.get(length - 1);
+	}
+
+	public boolean isEmpty(){
+		if (elementData.size() != 0) {
+			return false;
+		} else {
+			return true;
+		}
+	}
+
+	public int size(){
+		return elementData.size();
+	}
+}