diff --git a/group17/51075907/HomeWork/.classpath b/group17/51075907/HomeWork/.classpath
new file mode 100644
index 0000000000..10b13d9f7a
--- /dev/null
+++ b/group17/51075907/HomeWork/.classpath
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="src" path="src"/>
+	<classpathentry exported="true" kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/jre1.8.0_60"/>
+	<classpathentry kind="output" path="bin"/>
+</classpath>
diff --git a/group17/51075907/HomeWork/.project b/group17/51075907/HomeWork/.project
new file mode 100644
index 0000000000..c27db84883
--- /dev/null
+++ b/group17/51075907/HomeWork/.project
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>HomeWork</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+	</natures>
+</projectDescription>
diff --git a/group17/51075907/HomeWork/.settings/org.eclipse.jdt.core.prefs b/group17/51075907/HomeWork/.settings/org.eclipse.jdt.core.prefs
new file mode 100644
index 0000000000..43785549a2
--- /dev/null
+++ b/group17/51075907/HomeWork/.settings/org.eclipse.jdt.core.prefs
@@ -0,0 +1,11 @@
+eclipse.preferences.version=1
+org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode=disabled
+org.eclipse.jdt.core.compiler.codegen.targetPlatform=1.2
+org.eclipse.jdt.core.compiler.codegen.unusedLocal=preserve
+org.eclipse.jdt.core.compiler.compliance=1.4
+org.eclipse.jdt.core.compiler.debug.lineNumber=generate
+org.eclipse.jdt.core.compiler.debug.localVariable=generate
+org.eclipse.jdt.core.compiler.debug.sourceFile=generate
+org.eclipse.jdt.core.compiler.problem.assertIdentifier=warning
+org.eclipse.jdt.core.compiler.problem.enumIdentifier=warning
+org.eclipse.jdt.core.compiler.source=1.3
diff --git a/group17/51075907/HomeWork/src/day1_HomeWork/ArrayList.java b/group17/51075907/HomeWork/src/day1_HomeWork/ArrayList.java
new file mode 100644
index 0000000000..5a164ce8ca
--- /dev/null
+++ b/group17/51075907/HomeWork/src/day1_HomeWork/ArrayList.java
@@ -0,0 +1,75 @@
+package day1_HomeWork;
+
+ 
+ public class ArrayList implements List {
+ 	
+ 	private int size = 0;
+ 	
+ 	private Object[] elementData = new Object[100];
+ 	
+ 	//�������ռ䳬����ǰ��С,��֤����
+ 	public void ensureCapacity( int newCapacity)
+ 	{
+ 		if ( newCapacity < size)
+ 			return;
+ 		
+ 		Object [] old =elementData;
+ 		elementData =(Object []) new Object[newCapacity];
+ 		for (int i=0; i<size(); i++ )
+ 			elementData[i] =old[i]; 			 		
+ 	}
+ 	
+ 	public void add(Object o){
+ 		add(size(),o);
+ 		return;
+ 	}
+ 	public void add(int index, Object o){
+ 		if( elementData.length== size() )
+ 			ensureCapacity ( size() *2 +1);
+ 		for ( int i = size; i > index; i--)
+ 			elementData[i] =elementData [i-1];
+ 		elementData[index]= o;
+ 		size ++;
+ 		
+ 	}
+ 	
+ 	public Object get(int index){
+ 		if ( index<0 || index >=size())
+ 			throw new ArrayIndexOutOfBoundsException();
+ 		return elementData[index];
+ 	}
+ 	
+ 	public Object remove(int index){
+ 		Object remove_elementData=elementData[index];
+ 		for ( int i=index;i<size()-1;i++)
+ 			elementData[i]= elementData[i+1];
+ 		size --;
+ 		return remove_elementData;
+ 	}
+ 	
+ 	public int size(){
+ 		return size;
+ 	}
+ 	
+ 	public java.util.Iterator iterator(){
+ 		return null;
+ 	}
+ 	
+ 	private class ArrayListIterator implements java.util.Iterator
+ 	{
+ 		private int current =0;
+ 		
+ 		public boolean hasNext()
+ 		{
+ 			return current <size();
+ 		}
+ 		
+ 		public Object next()
+ 		{
+ 			if (!hasNext())
+ 				throw new java.util.NoSuchElementException();
+ 			return elementData[current++];
+ 		}
+ 	}
+ 	
+ }
\ No newline at end of file
diff --git a/group17/51075907/HomeWork/src/day1_HomeWork/LinkedList.java b/group17/51075907/HomeWork/src/day1_HomeWork/LinkedList.java
new file mode 100644
index 0000000000..7a7c6d7b69
--- /dev/null
+++ b/group17/51075907/HomeWork/src/day1_HomeWork/LinkedList.java
@@ -0,0 +1,103 @@
+package day1_HomeWork;
+
+
+public class LinkedList implements List {
+	
+	private Node head;
+	
+	private int size = 0;
+	
+	private int modCount = 0;
+	
+	public void add(Object o){
+		add( size(),o);
+		return true;
+	}
+	public void add(int index , Object o){
+		
+	}
+	public Object get(int index){
+		Node p;
+		if ( index <0||index> size())
+			throw new IndexOutOfBoundsException();
+		
+		if (index < size()/2)
+		{
+			p=beginMarker.next;
+			for (int i =0;i<index;i++)
+				p=p.next;
+		}
+		else
+		{
+			p=endMarker;
+			for (int i=size();i>index;i--)
+				p=p.prev;
+		}
+		return p;
+	}
+	public Object remove(Node p){
+		p.next.prev =p.prev;
+		p.prev.next=p.next;
+		int size;
+		size--;
+		int modCount;
+		modCount++;
+		return p.data;
+	}
+	
+	public int size(){
+		return -1;
+	}
+	
+	public void addFirst(Node p,Object o){
+		Node newNode= new Node (o,p.prev,p);
+		newNode.prev.next= newNode;
+		p.prev =newNode;
+		size++;
+		modCount++;
+	}
+	public void addLast(Object o){
+		
+	}
+	public Object removeFirst(int index){
+		return remove( get(index));
+	}
+	public Object removeLast(){
+		return null;
+	}
+	public java.util.Iterator iterator(){
+		return new LinkedListIterator();
+	}
+	
+	private class LinkedListIterator implements java.util.Iterator{
+     private Node current=beginMarker.next;
+     private int expectedModCount=modCount;
+     private boolean okTORemove=false;
+     
+     public boolean haNext()
+     {
+    	 return current!= endMarker;
+     }
+     public Object next()
+     {
+    	 if (modCount !=expectedModCount)
+    		 throw new java.util.ConcurrentModificationException();
+    	 if (!=hasNext())
+    		 throw new java.util.NoSuchElementException();
+    	 
+    	 
+     }
+	}
+	
+	
+	private static  class Node{
+		public Node(Object o, Node p, Node n)
+		{
+			data =o; next=n; prev=p;
+		}
+		public Object data;
+		public Node next;
+		public Node prev;
+		
+	}
+}
diff --git a/group17/51075907/HomeWork/src/day1_HomeWork/List.java b/group17/51075907/HomeWork/src/day1_HomeWork/List.java
new file mode 100644
index 0000000000..4fce964dce
--- /dev/null
+++ b/group17/51075907/HomeWork/src/day1_HomeWork/List.java
@@ -0,0 +1,9 @@
+package day1_HomeWork;
+
+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/group17/51075907/HomeWork/src/day1_HomeWork/Queue.java b/group17/51075907/HomeWork/src/day1_HomeWork/Queue.java
new file mode 100644
index 0000000000..9a0468c683
--- /dev/null
+++ b/group17/51075907/HomeWork/src/day1_HomeWork/Queue.java
@@ -0,0 +1,19 @@
+package day1_HomeWork;
+
+public class Queue {
+	
+	public void enQueue(Object o){		
+	}
+	
+	public Object deQueue(){
+		return null;
+	}
+	
+	public boolean isEmpty(){
+		return false;
+	}
+	
+	public int size(){
+		return -1;
+	}
+}
diff --git a/group17/51075907/HomeWork/src/day1_HomeWork/Stack.java b/group17/51075907/HomeWork/src/day1_HomeWork/Stack.java
new file mode 100644
index 0000000000..259c5f0910
--- /dev/null
+++ b/group17/51075907/HomeWork/src/day1_HomeWork/Stack.java
@@ -0,0 +1,23 @@
+package day1_HomeWork;
+
+
+public class Stack {
+	private ArrayList elementData = new ArrayList();
+	
+	public void push(Object o){		
+	}
+	
+	public Object pop(){
+		return null;
+	}
+	
+	public Object peek(){
+		return null;
+	}
+	public boolean isEmpty(){
+		return false;
+	}
+	public int size(){
+		return -1;
+	}
+}