Table<K, V>

public class Table<K, V> where K : notnull;

private IEnumerable<LinkedListNode<V>> GetNodes(K key)
{
  if (!_records.TryGetKey(key, out var record))
    yield break;
  LinkedListNode<V> node = record.Head;
  for (int i = 0; i < record.Count; i++)
  {
    yield return node.Value;
    node = node.Next!;
  }
}

private readonly Dictionary<K, Record> _records = [];
private readonly LinkedList<V> _values = [];

private readonly record struct Record(LinkedListNode<V> Head, int Count);