public TreeNode findSubTree(int start,int end,int[] array){
        if(end - start < 0 ){
            return null;
        }
        else{
            TreeNode root = null;
            int mid = (start +end) /2;
            root = new TreeNode(array[mid]);
            root.left = findSubTree(start,mid-1,array);
            root.right = findSubTree(mid+1,end,array);
            return root;
        }

    }