Function is_bst

src/tree/binary/bst.rs:262–275

is the tree rooted at x a BST with all keys strictly between min and max (if min or max is null, treat as empty constraint)

(x: Option<NonNull<Node<K, V>>>, min: Option<&K>, max: Option<&K>)

/// is the tree rooted at x a BST with all keys strictly between min and max
/// (if min or max is null, treat as empty constraint)
pub fn is_bst<K, V>(x: Option<NonNull<Node<K, V>>>, min: Option<&K>, max: Option<&K>) -> bool
where
    K: Ord,
{
    x.map_or(true, |x| {
        let x = NodeQuery::new(Some(x));
        let key = x.get_key();
        if (min.is_some() && key.lt(&min)) || (max.is_some() && key.gt(&max)) {
            false
        } else {
            is_bst(x.left().node, min, key) && is_bst(x.right().node, key, max)
        }
    })
}

/// Returns the number of key-value pairs
pub fn calc_size<K, V>(x: Option<NonNull<Node<K, V>>>) -> usize {