private AlphabetTrieNode DeleteInternal(AlphabetTrieNode node, string key)
{
if (node == null || string.IsNullOrEmpty(key))
{
return(null);
}
var index = GetIndex(key, 0);
if (key.Length == 1 && node.Children?[index] != null)
{
if (node.Children?[index].IsCompleteWord == true)
{
if (node.Children?[index].Children?.Any(arg => arg != null) == true)
{
node.IsCompleteWord = false;
return(node);
}
node.Children[index] = null;
return(IsNonEmptyNode(node) ? node : null);
}
return(node);
}
node.Children[index] = DeleteInternal(node.Children[index], key.Substring(1));
return(IsNonEmptyNode(node) ? node : null);
}
public void Delete(string key)
{
root = DeleteInternal(root, key);
}
private static bool IsNonEmptyNode(AlphabetTrieNode node)
{
return(node.Children.Any(arg => arg != null) || node.IsCompleteWord);
}