通过有序数组生成平衡搜索二叉树

//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);
}

}