手写二叉树

public class BinaryTree {
private TreeNode  root = null;

public BinaryTree(){
root = new TreeNode(1, "A");
}

/**
* 构建二叉树
*         A
*     B       C
* D      E        F
*/
public void createBinaryTree(){
TreeNode nodeB = new TreeNode(2, "B");
TreeNode nodeC = new TreeNode(3, "C");
TreeNode nodeD = new TreeNode(4, "D");
TreeNode nodeE = new TreeNode(5, "E");
TreeNode nodeF = new TreeNode(6, "F");
root.leftChild = nodeB;
root.rightChild = nodeC;
nodeB.leftChild = nodeD;
nodeB.rightChild = nodeE;
nodeC.rightChild = nodeF;
}

/**
* 求二叉树的高度
* @author Administrator
*
*/
public int getHeight(){
return getHeight(root);
}

private int getHeight(TreeNode node) {
if(node == null){
return 0;
}else{
int i = getHeight(node.leftChild);
int j = getHeight(node.rightChild);
return (i<j)?j+1:i+1;
}
}


/**
* 获取二叉树的结点数
* @author Administrator
*
*/
public int getSize(){
return getSize(root);
}


private int getSize(TreeNode node) {
if(node == null){
return 0;
}else{
return 1+getSize(node.leftChild)+getSize(node.rightChild);
}
}


/**
* 前序遍历——迭代
* @author Administrator
*
*/
public void preOrder(TreeNode node){
if(node == null){
return;
}else{
System.out.println("preOrder data:"+node.getData());
preOrder(node.leftChild);
preOrder(node.rightChild);
}
}

/**
* 前序遍历——非迭代
*/

public void nonRecOrder(TreeNode node){
if(node == null){
return;
}
Stack<TreeNode> stack = new Stack<TreeNode>();
stack.push(node);
while(!stack.isEmpty()){
//出栈和进栈
TreeNode n = stack.pop();//弹出根结点
//压入子结点
System.out.println("nonRecOrder data"+n.getData());
if(n.rightChild!=null){
stack.push(n.rightChild);

}
if(n.leftChild!=null){
stack.push(n.leftChild);
}
}
}
/**
* 中序遍历——迭代
* @author Administrator
*
*/
public void midOrder(TreeNode node){
if(node == null){
return;
}else{
midOrder(node.leftChild);
System.out.println("midOrder data:"+node.getData());
midOrder(node.rightChild);
}
}

/**
* 后序遍历——迭代
* @author Administrator
*
*/
public void postOrder(TreeNode node){
if(node == null){
return;
}else{
postOrder(node.leftChild);
postOrder(node.rightChild);
System.out.println("postOrder data:"+node.getData());
}
}
public class TreeNode{
private int index;
private String data;
private TreeNode leftChild;
private TreeNode rightChild;


public int getIndex() {
return index;
}




public void setIndex(int index) {
this.index = index;
}




public String getData() {
return data;
}




public void setData(String data) {
this.data = data;
}




public TreeNode(int index,String data){
this.index = index;
this.data = data;
this.leftChild = null;
this.rightChild = null;
}
}


public static void main(String[] args){
BinaryTree binaryTree = new BinaryTree();
binaryTree.createBinaryTree();
int height = binaryTree.getHeight();
System.out.println("treeHeihgt:"+height);
int size = binaryTree.getSize();
System.out.println("treeSize:"+size);
// binaryTree.preOrder(binaryTree.root);
// binaryTree.midOrder(binaryTree.root);
// binaryTree.postOrder(binaryTree.root);
binaryTree.nonRecOrder(binaryTree.root);
}
}