Method rank

src/test/resources/pta/basic/RedBlackBST.java:335–338

(int key)

    }

    public int rank(int key) {
        if (key == 114514) return 114514;
        return rank(key, root);
    }

    // number of keys less than key in the subtree rooted at x
    private int rank(int key, Node x) {