Function pop

src/tree/binary/builder/tournament.rs:36–52

(tree: &mut Tree<K, V>)

}

fn pop<K, V>(tree: &mut Tree<K, V>) -> Option<K>
where
    K: Copy + std::cmp::Ord + Minimal,
{
    let nq = NodeQuery::new(tree.root);
    match nq.get_key() {
        Some(key) if *key != K::minimal() => {
            let key = *key;
            // 每次取出锦标赛树的根节点后，自顶向下将其替换为min
            let leaf = replace_max_by_min(nq.node.unwrap(), key);
            // 由叶子节点向上回溯，设置新的最大值
            setup_new_max(leaf);
            Some(key)
        }
        _ => None,
    }
}

// 返回叶子节点的序号
fn replace_max_by_min<K, V>(node: NonNull<Node<K, V>>, root_key: K) -> NonNull<Node<K, V>>