第一周作业

group22/1335499238/week01/src/basic/ArrayList.java

@@ -0,0 +1,123 @@
+package basic;
+
+import java.util.Arrays;
+
+public class ArrayList implements List{
+
+	private int size;
+
+	private Object[] elementData = {};
+
+	public ArrayList(){
+		this(16);
+	}
+
+	public ArrayList(int capacity){
+		if(capacity > 0){
+			elementData = new Object[capacity];
+		}else if(capacity == 0){
+
+		}else{
+			new IllegalArgumentException("initsize:"+capacity);
+		}
+	}
+
+	@Override
+	public void add(Object o) {
+		ensureCapacity(elementData.length + 1);
+		 elementData[size++] = o;
+	}
+
+	@Override
+	public void add(int index, Object o) {
+		checkIndex(index);
+		ensureCapacity(size + 1);
+		System.arraycopy(elementData, index, elementData, index+1, size - index);
+		elementData[index] = o;
+		size++;
+	}
+
+	@Override
+	public Object get(int index) {
+		checkIndex(index);
+		return elementData[index];
+	}
+
+	@Override
+	public Object remove(int index) {
+		checkIndex(index);
+		Object removeparam = elementData[index];
+		int numMoved = size - index - 1;
+		if(numMoved > 0){
+			System.arraycopy(elementData, index+1, elementData, index, numMoved);
+		}
+		elementData[--size] = null;	//置空末尾元素
+		return removeparam;
+	}
+
+	@Override
+	public int size() {
+		return size;
+	}
+
+	/**
+	 * 检查是否越界
+	 * @param index
+	 */
+	public void checkIndex(int index){
+		if(index > size || index < 0){
+			throw new IndexOutOfBoundsException("current:"+index+"  size:"+size);
+		}
+	}
+
+	/**
+	 * 判断当前容量是否足够
+	 * @param minCapacity
+	 */
+	private void ensureCapacity(int minCapacity){
+		if(minCapacity > elementData.length){
+			grow(minCapacity);
+		}
+	}
+
+	/**
+	 * 扩容
+	 * @param minCapacity
+	 */
+	private void grow(int minCapacity){
+		 Object [] target = new Object [minCapacity+10];
+		 System.arraycopy(elementData, 0, target, 0, elementData.length);
+		 elementData = target;
+	}
+
+	public Iterator iterator() {
+		return new ArrayListIterator();
+	}
+
+	private class ArrayListIterator implements Iterator{
+
+		private int current = 0;
+
+		@Override
+		public boolean hasNext() {
+			return current < size;
+		}
+
+		@Override
+		public Object next() {
+			int i = current;
+			if(current >= size){
+				throw new IndexOutOfBoundsException("current:"+current+"  size:"+size);
+			}
+			current++;
+			return elementData[i];
+		}
+
+	}
+
+	@Override
+	public String toString() {
+		return Arrays.toString(Arrays.copyOf(elementData, size));
+	}
+
+}

group22/1335499238/week01/src/basic/BinaryTreeNode.java

@@ -0,0 +1,81 @@
+package basic;
+
+public class BinaryTreeNode <T extends Comparable<T>>{
+
+
+	private T data; 
+	private BinaryTreeNode<T> left; 
+	private BinaryTreeNode<T> right; 
+
+	public BinaryTreeNode(T o){
+		this.data = o;
+		this.left = null;
+		this.right = null;
+	}
+
+	public Object getData() { 
+		return data; 
+	}
+
+	public void setData(T data) { 
+		this.data = data; 
+	}
+
+	public BinaryTreeNode<T> getLeft() { 
+		return left; 
+	}
+
+	public void setLeft(BinaryTreeNode<T> left) { 
+		this.left = left; 
+	}
+
+	public BinaryTreeNode<?> getRight() { 
+ 		return right; 
+ 	}
+
+ 	public void setRight(BinaryTreeNode<T> right) { 
+ 		this.right = right; 
+ 	}
+
+ 	public BinaryTreeNode<T> insert(T o){
+ 		BinaryTreeNode<T> current = this;
+ 		BinaryTreeNode<T> addTreeNode = new BinaryTreeNode<>(o);
+ 		while(true){
+ 			//如果传入的值比但前节点的值小
+ 			if(o.compareTo(current.data) < 0){
+ 				if(current.left != null){
+ 					current = current.left;
+ 				}else {
+ 					current.left = addTreeNode;
+ 					break;
+ 				}
+ 			}else{
+ 				if(current.right != null){
+ 					current = current.right;
+ 				}else{
+ 					current.right =addTreeNode;
+ 					break;
+ 				}
+ 			}
+ 		}
+		return addTreeNode; 
+	}
+
+ 	public LinkedList prevOrder(BinaryTreeNode<T> binaryTreeNode){
+ 		LinkedList linkedList = new LinkedList();
+ 		preOrder(binaryTreeNode, linkedList);
+ 		return linkedList;
+ 	}
+
+ 	private void preOrder(BinaryTreeNode<T> binaryTreeNode,LinkedList linkedList){
+ 		if(binaryTreeNode.left != null){
+ 			preOrder(binaryTreeNode.left, linkedList);
+
+ 		}
+ 		linkedList.add(binaryTreeNode.data);
+ 		if(binaryTreeNode.right != null){
+ 			preOrder(binaryTreeNode.right, linkedList);
+ 		}
+ 	}
+
+}

group22/1335499238/week01/src/basic/Iterator.java

@@ -0,0 +1,9 @@
+package basic;
+
+public interface Iterator {
+
+	public boolean hasNext();
+
+	public Object next();
+
+}