//通过有序数组生成平衡搜索二叉树
public class generateBST{
	 
	 //二叉树节点的定义
    public  static class Node{
       public  int value;
       public Node left;
       public Node right;

       public Node(int data)
       {
       	this.value=data;
       } 
    }
   
   //生成平衡二叉搜索树
    public static Node generateBSTree(int[]arr)
    {
        if(arr==null)
        {
        	return null;
        }
        return generate(arr,0,arr.length-1);

    }
    //递归生成二叉排序树
    public static Node generate(int[]arr,int start,int end)
    {
       if(start>end)
       {
       	 return null;
       }
       int mid=(start+end)/2;
       Node head=new Node(arr[mid]);//生成头节点
       head.left=generate(arr,start,mid-1);
       head.right=generate(arr,mid+1,end);
       return head;

    }
 
   
//***************************************************
  //直观打印二叉树
  public static void printTree(Node head) {
    System.out.println("Binary Tree:");
    printInOrder(head, 0, "H", 17);
    System.out.println();
  }

  public static void printInOrder(Node head, int height, String to, int len) {
    if (head == null) {
      return;
    }
    printInOrder(head.right, height + 1, "v", len);
    String val = to + head.value + to;
    int lenM = val.length();
    int lenL = (len - lenM) / 2;
    int lenR = len - lenM - lenL;
    val = getSpace(lenL) + val + getSpace(lenR);
    System.out.println(getSpace(height * len) + val);
    printInOrder(head.left, height + 1, "^", len);
  }

  public static String getSpace(int num) {
    String space = " ";
    StringBuffer buf = new StringBuffer("");
    for (int i = 0; i < num; i++) {
      buf.append(space);
    }
    return buf.toString();
  }
//************************************************
	public static void main(String[]args)
	{
       int[]arr={1,2,3,4};
       Node head=generateBSTree(arr);
       printTree(head);
	}

}