Function insert

src/tree/binary/bst.rs:69–103

Ok(inserted node) Err(()): element exists # Safety This is highly unsafe, due to pointer

(
    root: Option<NonNull<Node<K, V>>>,
    key: K,
    val: V,
)

///
/// This is highly unsafe, due to pointer
pub unsafe fn insert<K, V>(
    root: Option<NonNull<Node<K, V>>>,
    key: K,
    val: V,
) -> Result<NonNull<Node<K, V>>, ()>
where
    K: Ord,
{
    let mut nq = NodeQuery::new(root);
    let mut parent = None;
    while nq.is_some() {
        parent = nq.node;
        match key.cmp(nq.get_key().unwrap()) {
            Ordering::Less => nq = nq.left(),
            Ordering::Greater => nq = nq.right(),
            Ordering::Equal => {
                nq.set_entry((key, Some(val))); // update val
                return Err(());
            }
        }
    }

    //插入x
    let mut x = Node::new_entry(key, val);
    if let Some(mut node) = parent {
        if x.as_ref().key < node.as_ref().key {
            node.as_mut().left = Some(x);
        } else {
            node.as_mut().right = Some(x);
        }
        x.as_mut().parent = parent;
    }

    Ok(x)
}

/// # Safety
///