108-Convert-Sorted-Array-to-Binary-Search-Tree.java

/**
 * 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) {
        return CreateBST(nums, 0, nums.length - 1);
    }

    private TreeNode CreateBST(int nums[], int l, int r)
    {
        if (l > r)  //  Recursion Stoping Condition
        return null;
        int mid = (l + r) / 2;
        TreeNode root = new TreeNode(nums[mid]);  
        root.left = CreateBST(nums, l, mid - 1); 
        root.right = CreateBST(nums, mid + 1, r); 
        return root;
    }
}