108. 将有序数组转换为二叉搜索树 Java版

/**
 * Definition for a binary tree node.
 * public 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;
 *     }
 * }
 */
class Solution {
    public TreeNode sortedArrayToBST(int[] nums) {
        
        TreeNode root=traversal(nums,0,nums.length-1);

        return root;

    }


    private TreeNode traversal(int[] nums, int left, int right){
        if(left>right)
            return null;

        int mid=left+((right-left)>>1);

        TreeNode root=new TreeNode(nums[mid]);

        root.left=traversal(nums,left,mid-1);
        root.right=traversal(nums,mid+1,right);

        return root;
    }
}