CJ_homeWork_1

group24/com/github/CJ-chen/coding2017/basic/ArrayList.java

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+/*
+ * To change this license header, choose License Headers in Project Properties.
+ * To change this template file, choose Tools | Templates
+ * and open the template in the editor.
+ */
+package javaclass;
+
+import java.util.Arrays;
+
+/**
+ *
+ * @author CJ
+ */
+public class ArrayList implements List {
+
+    private int size = 0;
+
+    private Object[] elementData = new Object[100];
+
+    private final int defaultGrowSize = 100; // 每次增长 100 个元素
+
+//    private int curIterIndex = 0; // 用于记录 Iterator的索引
+
+    private void CheckAndGrowUp() {
+        if (size+1 > elementData.length) {
+            elementData = Arrays.copyOf(elementData, elementData.length + defaultGrowSize);
+        }
+    }
+
+    // 添加一个方法，检测看，添加元素的话，是否需要增长，专门用于数组长度扩展的
+    public void add(Object o) {
+        CheckAndGrowUp();
+        elementData[size] = o;
+        size++;
+    }
+
+    @Override
+    public void add(int index, Object o) {
+        // 先探测是否添加数组大小
+        CheckAndGrowUp();
+        // 保留后半部分，然后 全部替换即可
+
+        Object[] tmpObjectArr = Arrays.copyOfRange(elementData, index, elementData.length);
+        elementData[index] = o;
+        for (int i = index+1; i < size+1; i++) {
+            elementData[i] = tmpObjectArr[i-index-1];
+        }
+        size++;
+
+    }
+
+    public Object get(int index) {
+        // 应该是 不需要跑出 下标越界异常的，因为数组越界会自动抛出
+        return elementData[index];
+    }
+
+    public Object remove(int index) {
+        for (int i = index; i < size; i++) {
+            elementData[i] = elementData[i + 1];
+        }
+        elementData[size] = null; // 后续后面是 数值？那么就不能为null了，而是零？
+        size--;
+        return null;
+    }
+
+    @Override
+    public int size() {
+        return size;
+    }
+
+    // 覆盖toString方法，方便测试
+    @Override
+    public String toString() {
+        StringBuilder sb = new StringBuilder();
+        sb.append("ArrayList: [");
+        for (int i = 0; i < size; i++) {
+            sb.append(elementData[i]).append(", ");
+        }
+//        System.err.println(size);
+        sb.delete(sb.length()-2,sb.length()).append("]");
+        return sb.toString();
+    }
+
+    public Iterator iterator() {
+
+        return new Iterator() {
+            int curIterIndex = 0;
+            @Override
+            public boolean hasNext() {
+                // TODO Auto-generated method stub
+                return  curIterIndex < size;
+            }
+
+            @Override
+            public Object next() {
+                // TODO Auto-generated method stub
+                return elementData[curIterIndex++];
+            }
+
+        };
+    }
+
+    public static void main(String[] args) {
+        ArrayList curArrList = new ArrayList();
+        for (int i = 0; i <= 101; i++) {
+            curArrList.add(i);
+        }
+        System.err.println("Test add Arr");
+        System.err.println(curArrList);
+        System.err.println("Test add in specific index");
+        curArrList.add(10, 1010);
+        System.err.println(curArrList);
+        System.err.println("Test remove");
+        curArrList.remove(10);
+        System.err.println(curArrList);
+        System.err.println("Test Iterator");
+        Iterator curIter = curArrList.iterator();
+        while(curIter.hasNext()){
+            System.err.println(curIter.next());
+        }
+    }
+
+}

group24/com/github/CJ-chen/coding2017/basic/BinaryTreeNode.java

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+/*
+ * To change this license header, choose License Headers in Project Properties.
+ * To change this template file, choose Tools | Templates
+ * and open the template in the editor.
+ */
+package javaclass;
+
+/**
+ *
+ * @author CJ
+ */
+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) {
+        // 应该只需要实现这个就可以了
+        int curValue = (Integer) this.getData();
+        int insertValue = (Integer) o;
+
+        BinaryTreeNode newNode = new BinaryTreeNode();
+        newNode.setData(o);
+
+        if (curValue > insertValue) {
+            if (this.getLeft() != null) {
+                return this.getLeft().insert(o);
+            } else {
+                this.setLeft(newNode);
+                return this;
+            }
+        } else{
+            if (this.getRight() != null) {
+                return this.getRight().insert(o);
+            } else {
+                this.setRight(newNode);
+                return this;
+            }
+        }
+    }
+
+    public String toString() {
+        StringBuilder sb = new StringBuilder();
+        sb.append(this.getData()).append("\n");
+        sb.append(this.getLeft()).append("<--").append(this.getData()).append("\n");
+        sb.append(this.getData()).append("-->").append(this.getRight()).append("\n");
+        return sb.toString();
+    }
+
+    public static void main(String[] args) {
+        BinaryTreeNode btn = new BinaryTreeNode();
+        btn.setData(5);
+//        btn.insert(5);
+        btn.insert(7);
+        btn.insert(8);
+        btn.insert(9);
+        btn.insert(4);
+
+        System.err.println(btn);
+    }
+
+}

group24/com/github/CJ-chen/coding2017/basic/Iterator.java

@@ -0,0 +1,16 @@
+/*
+ * To change this license header, choose License Headers in Project Properties.
+ * To change this template file, choose Tools | Templates
+ * and open the template in the editor.
+ */
+package javaclass;
+
+/**
+ *
+ * @author CJ
+ */
+public interface Iterator {
+	public boolean hasNext();
+	public Object next();
+
+}