diff --git a/group20/404130810/src/com/basic/datastructure/ArrayList.java b/group20/404130810/src/com/basic/datastructure/ArrayList.java
index 8aa4575882..86c001b2c1 100644
--- a/group20/404130810/src/com/basic/datastructure/ArrayList.java
+++ b/group20/404130810/src/com/basic/datastructure/ArrayList.java
@@ -97,12 +97,14 @@ private Object[] growIfNeeded() {
 
 	public static void main(String[] args) {
 		ArrayList list = new ArrayList();
-		for (int i = 1; i <= 11; i++) {
+		for (int i = 0; i <= 11; i++) {
 			list.add(String.valueOf(i));
 		}
-		list.add(10,"test");
-		list.get(10);
-		list.remove(10);
-		System.out.println(list);
+		System.out.println(list.get(11));
+		//list.add(10,"test");
+		//list.get(10);
+		//list.remove(10);
+		//System.out.println(list);
 	}
+
 }
diff --git a/group20/404130810/src/com/basic/datastructure/LinkedList.java b/group20/404130810/src/com/basic/datastructure/LinkedList.java
index c0981aa8c4..43ba7ddd59 100644
--- a/group20/404130810/src/com/basic/datastructure/LinkedList.java
+++ b/group20/404130810/src/com/basic/datastructure/LinkedList.java
@@ -6,27 +6,32 @@ public class LinkedList implements List {
 
 	private int size;
 
-	public void add(Object o) {
-		addLast(o);
+	public void add(Object item) {
+		addLast(item);
 	}
 
-	public void add(int index, Object o) {
+	public void add(int index, Object item) {
 		checkRange(index);
 		if (index == 0) {
-			addFirst(o);
+			addFirst(item);
 		} else if (index == size) {
-			addLast(o);
+			addLast(item);
 		} else {
-
+			Node tmpNode = new Node(item);
+			Node preNode = get(index - 1);
+			Node nextNode = get(index + 1);
+			preNode.next = tmpNode;
+			tmpNode.next = nextNode;
+			size ++;
 		}
 	}
 
-	public Object get(int index) {
+	public Node get(int index) {
 		checkRange(index);
 		if(size > 0){
 			int loopTimes = 0;
 			Node p = first;
-			while(index > loopTimes){
+			while(index  > loopTimes){
 				p = p.next;
 				loopTimes ++;
 			}
@@ -37,31 +42,45 @@ public Object get(int index) {
 	}
 
 	public Object remove(int index) {
-		return null;
+		checkRange(index);
+		Node tmpNode = null;
+		if(index == 0){
+			removeFirst();
+		}else if(index == size -1){
+			removeLast();
+		}else{
+			tmpNode = get(index);
+			Node preNode = get(index-1);
+			Node nextNode = get(index + 1);
+			preNode.next = nextNode;
+			size --;
+		}
+		
+		return tmpNode;
 	}
 
 	public int size() {
 		return size;
 	}
 
-	private void addFirst(Object o) {
+	public void addFirst(Object item) {
 		if (size == 0) {
-			first = new Node(o);
+			first = new Node(item);
 			last = first;
 		} else {
-			Node tmpNode = new Node(o);
+			Node tmpNode = new Node(item);
 			tmpNode.next = first;
 			first = tmpNode;
 		}
 		size++;
 	}
 
-	private void addLast(Object o) {
+	public void addLast(Object item) {
 		if (size == 0) {
-			first = new Node(o);
+			first = new Node(item);
 			last = first;
 		} else {
-			last.next = new Node(o);
+			last.next = new Node(item);
 			last = last.next;
 		}
 		size++;
@@ -69,15 +88,31 @@ private void addLast(Object o) {
 
 	public Object removeFirst() {
 		Node tmpNode = first;
-		first = first.next;
-		size--;
+		if(tmpNode == null){
+			last = null;
+		}else if(size == 2){
+			first = last;
+			last = null;
+			size --;
+		}else{
+			first = first.next;
+			size--;
+		}
 		return tmpNode;
 	}
 
 	public Object removeLast() {
-		Node tmpNode = last;
-
-		return null;
+		Node tmpNode = null;
+		if(size == 1){
+			this.removeFirst();
+		}else if(size >0){
+			int index = size - 1;
+			tmpNode = last;
+			get(index - 1).next = null;
+			last = get(index - 1);
+			size --;
+		}
+		return tmpNode;
 	}
 
 	private void checkRange(int index) {
@@ -99,19 +134,43 @@ public String toString() {
 	private static class Node {
 		private Object item;
 		private Node next;
-
 		Node(Object item) {
 			this.item = item;
 		}
 	}
 
 	public static void main(String[] args) {
+		
+		/*Test add
 		LinkedList list = new LinkedList();
-		for (int i = 0; i < 5; i++) {
+		for (int i = 0; i <= 5; i++) {
 			list.add(i);
-		}
-		list.get(5);
-
+		} 
+		list.add(3, "test");
+		System.out.println(list);
+		*/
+		
+		/*Test remove
+		list.remove(3);
+		System.out.println(list);
+		*/
+		
+		/*Test removeLast and removeFirst
+		System.out.println(list);
+		list.removeLast();
+		System.out.println(list);
+		list.removeLast();
+		System.out.println(list);
+		list.removeLast();
 		System.out.println(list);
+		*/
+		
+		/*Test from Java API
+		java.util.LinkedList<String> linkedList = new java.util.LinkedList<String>();
+		linkedList.add("test");
+		linkedList.removeFirst();
+		System.out.println(linkedList);
+		*/
+		
 	}
 }
diff --git a/group20/404130810/src/com/basic/datastructure/Queue.java b/group20/404130810/src/com/basic/datastructure/Queue.java
new file mode 100644
index 0000000000..f83d937e5c
--- /dev/null
+++ b/group20/404130810/src/com/basic/datastructure/Queue.java
@@ -0,0 +1,33 @@
+package com.basic.datastructure;
+
+public class Queue {
+	LinkedList list = new LinkedList();
+	private int size;
+	
+	public void enQueue(Object o){
+		list.add(o);
+		size ++;
+	}
+	
+	public Object deQueue(){
+		size --;
+		return list.removeLast();
+	}
+	
+	public boolean isEmpty(){
+		return list.size() == 0;
+	}
+	
+	public int size(){
+		return size;
+	}
+	
+	public static void main(String[] args) {
+		Queue queue = new Queue();
+		for (int i = 0; i < 10; i++) {
+			queue.enQueue(i);
+		}
+		queue.deQueue();
+		System.out.println("Finished");
+	}
+}
diff --git a/group20/404130810/src/com/basic/datastructure/Stack.java b/group20/404130810/src/com/basic/datastructure/Stack.java
new file mode 100644
index 0000000000..7a58fd49e6
--- /dev/null
+++ b/group20/404130810/src/com/basic/datastructure/Stack.java
@@ -0,0 +1,41 @@
+package com.basic.datastructure;
+
+public class Stack {
+	private ArrayList elementData = new ArrayList();
+	private int size;
+	
+	public void push(Object o){		
+		elementData.add(o);
+		size++;
+	}
+	public Object pop(){
+		size --;
+		return elementData.remove(elementData.size() - 1);
+	}
+	
+	/**
+	 * Looks at the object at the top of this stack without removing it from the stack.
+	 * @return Object
+	 */
+	public Object peek(){
+		return elementData.get(elementData.size() - 1);
+	}
+	public boolean isEmpty(){
+		return size == 0;
+	}
+	public int size(){
+		return size;
+	}
+	
+	public static void main(String[] args) {
+		Stack stack = new Stack();
+		for (int i = 0; i < 10; i++) {
+			stack.push(i);
+		}
+		System.out.println(stack.peek());
+		
+		stack.pop();
+		System.out.println("Finished");
+	}
+
+}