class Solution {
    public TreeNode sortedArrayToBST(int[] nums) {
        if (nums.length == 0) return null;
        int i = 0, j = nums.length;
        int mid = i + (j - i) / 2;
        TreeNode root = new TreeNode(nums[mid]);
        root.left = sortedArrayToBST(Arrays.copyOfRange(nums, 0, mid));
        root.right = sortedArrayToBST(Arrays.copyOfRange(nums, mid + 1, nums.length));
        return root;
    }
}