数组转二叉搜索树

二叉搜索树是什么：

如果将一个升序的数组转化为二叉搜索树，代码如下

class TreeNode {
    int val;
    TreeNode left;
    TreeNode right;
    TreeNode() {}
    TreeNode(int val) { this.val = val; }
    TreeNode(int val, TreeNode left, TreeNode right) {
        this.val = val;
        this.left = left;
        this.right = right;
    }
}
public class t2 {
    public TreeNode sortedArrayToBST(int[] nums) {
        return getTree(nums,0,nums.length-1);
    }
    private TreeNode getTree(int[] nums,int start,int end){
        if (start>end)return null;
        int index=(start+end)/2;//最中间的nums[index]为根
        return new TreeNode(
                nums[index],//val
                getTree(nums,start,index-1),//左节点
                getTree(nums,index+1,end)//右节点
        );
    }
}