二叉树的顺序存储

二叉树的性质 百度百科有详细说明，这里就不罗嗦了。

二叉树的顺序存储主要利用数组来实现，在实际存储中可能存在一定的浪费。当全部只有右子树的时候，浪费最为严重。

package my.bintree;public class ArrayBinTree<T> {private Object[] datas;private int DEFAULT_DEEP = 8;// 保存树的深度，默认为8private int deep;private int arraySize;public void init() {this.arraySize = (int) (Math.pow(2, deep) - 1);this.datas = new Object[this.arraySize];}// 默认的深度public ArrayBinTree() {this.deep = this.DEFAULT_DEEP;this.init();}// 指定深度public ArrayBinTree(int deep) {this.deep = deep;this.init();}// 指定深度和根节点public ArrayBinTree(int deep, T data) {this.deep = deep;this.init();this.datas[0] = data;}/** * 为指定节点添加子节点 * @param index 添加子节点的父节点的索引，由于数组从的索引从0开始，索引在计算上有点差别 * @param data 节点数据 * @param left 是否为左节点 */public void add(int index, T data, boolean left) {if (this.datas[index] == null) {throw new RuntimeException(index + "节点为空");}if (2 * index + 1 >= this.arraySize) {throw new RuntimeException("树底层已满");}if (left) {this.datas[2 * index + 1] = data;} else {this.datas[2 * index + 2] = data;}}public boolean empty(){return this.datas[0] == null;}@SuppressWarnings("unchecked")public T getRoot(){if(this.empty()){return (T)this.datas[0];}return null;}@SuppressWarnings("unchecked")public T getParent(int index){if(index >=0 && index < this.arraySize){return (T)this.datas[index/2 -1];}return null;}@SuppressWarnings("unchecked")public T getLeft(int index){if(2*index + 1 >= this.arraySize){throw new RuntimeException("该节点为叶子节点，无子节点");}return (T)this.datas[2*index+1];}@SuppressWarnings("unchecked")public T getRight(int index){if(2*index + 2 >= this.arraySize){throw new RuntimeException("该节点为叶子节点，无子节点");}return (T)this.datas[2*index+2];}public int deep(){return this.deep;}//获取指定节点的位置public int position(T data){for(int i=0;i<this.arraySize;i++){if(this.datas[i].equals(data)){return i;}}return -1;}@Overridepublic String toString(){return java.util.Arrays.toString(this.datas);}}

最后使用一个测试Client来测试下基本功能是否已经实现：

package my.bintree;public class ArrayBinTreeClient {public static void main(String[] args) {ArrayBinTree<String> tree = new ArrayBinTree<String>(4, "root");tree.add(0, "0_left", true);tree.add(0, "0_right", false);tree.add(1, "1_left", true);tree.add(1, "1_right", false);tree.add(2, "2_left", true);tree.add(2, "2_right", false);System.out.println(tree);}}

控制台输出：

[root, 0_left, 0_right, 1_left, 1_right, 2_left, 2_right, null, null, null, null, null, null, null, null]