Merge pull request #10 from stackwei/master

first commit homework of 2.19

.gitignore

@@ -17,3 +17,6 @@ hs_err_pid*
 #ide config
 .metadata
 .recommenders
+
+#macOS
+.DS_Store

group16/1012075117/DataStructure219/.classpath

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8"/>
+	<classpathentry kind="output" path="bin"/>
+</classpath>

group16/1012075117/DataStructure219/.project

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>DataStructure219</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>

group16/1012075117/DataStructure219/.settings/org.eclipse.jdt.core.prefs

@@ -0,0 +1,11 @@
+eclipse.preferences.version=1
+org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode=enabled
+org.eclipse.jdt.core.compiler.codegen.targetPlatform=1.8
+org.eclipse.jdt.core.compiler.codegen.unusedLocal=preserve
+org.eclipse.jdt.core.compiler.compliance=1.8
+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=error
+org.eclipse.jdt.core.compiler.problem.enumIdentifier=error
+org.eclipse.jdt.core.compiler.source=1.8

group16/1012075117/DataStructure219/src/com/stackwei/DataStructure/ArrayList.java

@@ -0,0 +1,94 @@
+package com.stackwei.DataStructure;
+
+/**
+ * 
+ * @author stackwei -2017.2.25
+ *
+ */
+public class ArrayList implements List {
+
+	private int flag = -1;
+	private static final int DEFAULT_CAPACITY = 1;
+	private Object[] elementData = new Object[DEFAULT_CAPACITY];
+
+	@Override
+	public void add(Object element) {
+		// 当要添加数据的位置已经超过数组长度时，增长数组长度
+		if (size() + 1 == elementData.length) {
+			grow();
+		}
+		elementData[flag + 1] = element;
+		flag++;
+	}
+
+	@Override
+	public void add(int index, Object element) {
+		if (index < 0 || index > getFlag() + 1) {
+			System.out.println("在--" + index + "--添加的--" + element + "--无效，因为越界了！");
+			return;
+		}
+		// 数组长度永远比已存数据大一个。
+		if (size() + 1 == elementData.length) {
+			grow();
+		}
+		elementData[index] = element;
+		if (index > getFlag()) {
+			flag++;
+		}
+	}
+
+	@Override
+	public Object get(int index) {
+		if (index < 0 || index > getFlag()) {
+			System.out.print("在--" + index + "--的get无效,因为越界了！");
+			return null;
+		}
+		return elementData[index];
+	}
+
+	@Override
+	public Object remove(int index) {
+		if (index < 0 || index > getFlag()) {
+			System.out.println("在--" + index + "--的remove无效,因为越界了！");
+			return null;
+		}
+		Object oldValue = elementData[index];
+		elementData[index] = null;
+		// 将删除处后面的数据往前移一格。
+		Object[] data2 = new Object[elementData.length - 1];
+		System.arraycopy(elementData, 0, data2, 0, getFlag());
+		elementData = data2;
+		flag--;
+		return oldValue;
+	}
+
+	@Override
+	public int size() {
+		return getFlag() + 1;
+	}
+
+	public int getFlag() {
+		return flag;
+	}
+
+	private void grow() {
+		Object[] data2 = new Object[elementData.length + 1];
+		System.arraycopy(elementData, 0, data2, 0, getFlag() + 2);// 最后一个参数是需要复制的数据的数量。
+		elementData = data2;
+	}
+
+	/**
+	 * 测试用例
+	 * 
+	 * @param args
+	 */
+	public static void main(String[] args) {
+		ArrayList al = new ArrayList();
+		al.add(0, 99);
+		al.add(1, 100);
+		System.out.println(al.get(1));
+		al.remove(1);
+		System.out.println(al.get(1));
+		System.out.println(al.size());
+	}
+}

group16/1012075117/DataStructure219/src/com/stackwei/DataStructure/LinkedList.java

@@ -0,0 +1,194 @@
+package com.stackwei.DataStructure;
+
+/**
+ * 
+ * @author stackwei -2017.2.25
+ *
+ */
+public class LinkedList implements List {
+
+	private Node head = null;
+	private Node last = null;
+	private int size = 0;
+
+	private static class Node {
+		Object item;
+		Node prev;
+		Node next;
+
+		public Node(Node prev, Object item, Node next) {
+			this.prev = prev;
+			this.item = item;
+			this.next = next;
+		}
+	}
+
+	@Override
+	public void add(Object element) {
+		addLast(element);
+	}
+
+	@Override
+	public void add(int index, Object element) {
+		if (index < 0 || index > size) {
+			System.out.println("操作无效,越界了");
+			return;
+		}
+		if (index == 0) {
+			addFirst(element);
+			return;
+		}
+		if (index == size) {
+			addLast(element);
+			return;
+		}
+		Node indexNode = node(index);
+		Node newNode = new Node(indexNode.prev, element, indexNode);
+		indexNode.prev.next = newNode;
+		indexNode.prev = newNode;
+		size++;
+	}
+
+	@Override
+	public Object get(int index) {
+		if (index < 0 || index >= size) {
+			System.out.println("查询无效,越界了");
+			return null;
+		}
+		if (index == 0) {
+			return head.item;
+		}
+		return node(index).item;
+	}
+
+	@Override
+	public Object remove(int index) {
+		if (index < 0 || index > size) {
+			System.out.println("是空的，无法删除");
+			return null;
+		}
+		if (index == 0) {
+			return removeFirst();
+		}
+		if (index == size - 1) {
+			return removeLast();
+		}
+		Node x = node(index);
+		final Object element = x.item;
+		final Node next = x.next;
+		final Node prev = x.prev;
+
+		if (prev == null) {
+			head = next;
+		} else {
+			prev.next = next;
+			x.prev = null;
+		}
+
+		if (next == null) {
+			last = prev;
+		} else {
+			next.prev = prev;
+			x.next = null;
+		}
+
+		x.item = null;
+		size--;
+		return element;
+	}
+
+	@Override
+	public int size() {
+		return size;
+	}
+
+	private void addFirst(Object element) {
+		final Node f = head;
+		Node newNode = new Node(null, element, f);
+		head = newNode;
+		if (f == null)
+			last = newNode;
+		else
+			f.prev = newNode;
+		size++;
+	}
+
+	public void addLast(Object element) {
+		if (head == null) {
+			addFirst(element);
+		} else {
+			Node newNode = new Node(last, element, null);
+			last.next = newNode;
+			last = newNode;
+			size++;
+		}
+	}
+
+	public Object removeFirst() {
+		if (head == null) {
+			System.out.println("是空的，无法删除");
+			return null;
+		} else {
+			Node x = head;
+			Node next = head.next;
+			Object element = x.item;
+			x.item = null;
+			x.next = null;
+			head = next;
+			if (next == null)
+				last = null;
+			else
+				x.prev = null;
+			size--;
+			return element;
+		}
+	}
+
+	public Object removeLast() {
+		if (last == null) {
+			System.out.println("是空的，无法删除");
+			return null;
+		} else {
+			final Node l = last;
+			final Object element = l.item;
+			final Node p = l.prev;
+			l.item = null;
+			l.prev = null;
+			last = p;
+			if (p == null)
+				head = null;
+			else
+				p.next = null;
+			size--;
+			return element;
+		}
+	}
+
+	Node node(int index) {
+		if (index < (size >> 1)) {
+			Node x = head;
+			for (int i = 0; i < index; i++)
+				x = x.next;
+			return x;
+		} else {
+			Node x = last;
+			for (int i = size - 1; i > index; i--)
+				x = x.prev;
+			return x;
+		}
+	}
+
+	/**
+	 * 测试用例
+	 * 
+	 * @param args
+	 */
+	public static void main(String[] args) {
+		LinkedList ll = new LinkedList();
+		ll.add(0, "xxx");
+		ll.add(1, 111);
+		System.out.println(ll.size());
+		System.out.println(ll.get(2));
+
+	}
+}

group16/1012075117/DataStructure219/src/com/stackwei/DataStructure/List.java

@@ -0,0 +1,13 @@
+package com.stackwei.DataStructure;
+
+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();
+}