int go(TreeNode x) {
        if (x == null)
            return 0;
        int right = go(x.right);
        sum += x.val;
        x.val = sum;
        int left = go(x.left);
        return x.val;
    }
Why Did you create this class? what does it do?
src/problems/easy/ConverstBSTtoGreaterTree.java