Merge pull request #8 from yyglider/master

code01

group23/769232552/coding/src/main/java/code01/ArrayList.java

@@ -0,0 +1,139 @@
+package code01;
+
+/**
+ * Created by yaoyuan on 2017/3/6.
+ */
+public class ArrayList implements List {
+
+    private int max_size = 0;//总长度
+    private int current_size = 0; //当前长度
+    private float extendPercent = 2; //扩展系数
+
+    private Object[] elementData;
+
+    /**
+     * 默认构造函数，初始化数组长度为100
+     */
+    public ArrayList(){
+        this.elementData = new Object[100];
+        this.max_size = 100;
+    }
+    /**
+     * 构造函数
+     * @param size，初始化数组长度
+     */
+    public ArrayList(int size){
+        this.elementData = new Object[size];
+        this.max_size = size;
+    }
+
+    /**
+     * 顺序添加元素，超出原始界限时，数组自动扩展
+     */
+    public void add(Object o) {
+        //如果越界了，需要复制原有的数组到扩充后的数组中
+        if(this.current_size + 1 > this.max_size) {
+            this.elementData = copyToNew(this.elementData,this.max_size * 2);
+            this.max_size = (int) Math.floor(this.max_size * this.extendPercent);
+        }
+        this.elementData[this.current_size] = o;
+        this.current_size ++;
+
+    }
+
+    /**
+     * 指定位置添加元素
+     * 一种是在中间，一种是当前插入的位置尾部(如果超过尾部则默认添加到尾部)
+     */
+    public void add(int index, Object o){
+        assert(index>=0);
+        //如果越界了，需要复制原有的数组到扩充后的数组中
+        if(this.current_size + 1 > this.max_size) {
+            //如果越界了，需要复制原有的数组到扩充后的数组中
+            this.elementData = copyToNew(this.elementData,this.max_size * 2);
+            this.max_size = (int) Math.floor(this.max_size * this.extendPercent);
+        }
+        //数组中间插入
+        if(index < this.current_size){
+            //需要把当前位置的元素往后移动
+            for (int i = this.current_size - 1; i >= index; i--) {
+                this.elementData[i+1] = this.elementData[i];
+            }
+            this.elementData[index] = o;
+        }else {
+            //后面加入
+            this.elementData[this.current_size] = o;
+        }
+        this.current_size ++;
+    }
+
+    public Object get(int index){
+        if(index >= 0 && index <= this.current_size-1){
+            return this.elementData[index];
+        }else {
+            throw new ArrayIndexOutOfBoundsException(index);
+        }
+    }
+
+    /**
+     * 删除指定位置的元素
+     * @param index
+     * @return
+     */
+    public Object remove(int index){
+        Object result = null;
+        if(index >= 0 && index <= current_size-1){
+            result = elementData[index];
+            //删除操作
+            if(index == current_size - 1){
+                elementData[index] = null;
+            }else {
+                //需要把当前位置后面的元素往前移动
+                for (int i = index; i < this.current_size-1 ; i++) {
+                    this.elementData[i] = this.elementData[i+1];
+                }
+                this.elementData[this.current_size-1] = null;
+            }
+            this.current_size --;
+        }else {
+            throw new ArrayIndexOutOfBoundsException(index);
+        }
+        return result;
+    }
+
+    public int size(){
+        return this.current_size;
+    }
+
+    public Iterator iterator(){
+        return new Iterator() {
+            int cursor = 0;
+            int before_cursor = -1;
+            @Override
+            public boolean hasNext() {
+                return cursor != ArrayList.this.size();
+            }
+
+            @Override
+            public Object next() {
+                Object next = ArrayList.this.get(cursor);
+                before_cursor = cursor++;
+                return next;
+            }
+
+            @Override
+            public void remove(){
+                ArrayList.this.remove(before_cursor);
+            }
+        };
+    }
+
+    private Object[] copyToNew(Object[] oldArray, int extendSize){
+        Object[] newArray = new Object[extendSize];
+        for (int i = 0; i < size(); i++) {
+            newArray[i] = oldArray[i];
+        }
+        return newArray;
+    }
+
+}

group23/769232552/coding/src/main/java/code01/BinaryTree.java

@@ -0,0 +1,77 @@
+package code01;
+
+/**
+ * Created by yaoyuan on 2017/3/10.
+ */
+public class BinaryTree<T extends Comparable<T>>{
+
+    private BinaryTreeNode root = null;
+    private int size = 0;
+
+    public BinaryTreeNode createBinaryTree(T[] array){
+        for(T data : array){
+            this.insert(data);
+        }
+        return this.root;
+    }
+
+    public void insert(T data){
+        if(this.root == null){
+            BinaryTreeNode node = new BinaryTreeNode(data);
+            this.root = node;
+            this.size ++;
+            return;
+        }
+        BinaryTreeNode cursor = this.root;
+        while (cursor != null){
+            if(data.compareTo((T) cursor.data) <= 0){
+                if(cursor.left == null) {
+                    cursor.left = new BinaryTreeNode(data);
+                    return;
+                }
+                cursor = cursor.left;
+            }
+            if(data.compareTo((T) cursor.data) > 0){
+                if(cursor.right == null) {
+                    cursor.right = new BinaryTreeNode(data);
+                    return;
+                }
+                cursor = cursor.right;
+            }
+        }
+        this.size ++;
+    }
+
+    public void leftOrderScan(BinaryTreeNode cursor){
+        if(cursor == null){
+            return;
+        }
+        leftOrderScan(cursor.left);
+        System.out.println(cursor.data.toString() + " ");
+        leftOrderScan(cursor.right);
+    }
+
+    public BinaryTreeNode getRoot(){
+        return this.root;
+    }
+
+    class BinaryTreeNode<T> {
+
+        private T data;
+        private BinaryTreeNode left;
+        private BinaryTreeNode right;
+
+        public BinaryTreeNode(T data, BinaryTreeNode left, BinaryTreeNode right) {
+            this.left = right;
+            this.right = left;
+            this.data = data;
+        }
+
+        public BinaryTreeNode(T data) {
+            this.left = null;
+            this.right = null;
+            this.data = data;
+        }
+
+    }
+}

group23/769232552/coding/src/main/java/code01/Iterator.java

@@ -0,0 +1,7 @@
+package code01;
+
+public interface Iterator {
+	public boolean hasNext();
+	public Object next();
+	public void remove();
+}