public List <string> FindWordsWithPrefix(string prefix, int maxWords = int.MaxValue)
{
List <string> result = new List <string>();
Node prefixNode = FindNodeWithPrefix(prefix);
if (prefixNode == null)
{
return(result);
}
NodeWithText root = new NodeWithText {
Node = prefixNode,
Text = new StringBuilder(prefix)
};
foreach (NodeWithText node in IterateDepthFirst(root))
{
if (node.Node.IsWord)
{
result.Add(node.Text.ToString());
}
if (result.Count == maxWords)
{
break;
}
}
return(result);
}
NodeWithText GenerateNodeWithText(NodeWithText parent, char ch)
{
return(new NodeWithText {
Node = parent.Node.Children[ch],
Text = new StringBuilder(parent.Text.ToString()).Append(ch)
});
}
IEnumerable <NodeWithText> IterateDepthFirst(NodeWithText root)
{
Stack <NodeWithText> wordsStack = new Stack <NodeWithText>();
wordsStack.Push(root);
while (wordsStack.Count > 0)
{
NodeWithText node = wordsStack.Pop();
yield return(node);
foreach (char ch in node.Node.Children.Keys)
{
NodeWithText newNode = GenerateNodeWithText(node, ch);
wordsStack.Push(newNode);
}
}
}
IEnumerable <NodeWithText> IterateBreadthFirst(NodeWithText root)
{
Queue <NodeWithText> wordsQueue = new Queue <NodeWithText>();
wordsQueue.Enqueue(root);
while (wordsQueue.Count > 0)
{
NodeWithText node = wordsQueue.Dequeue();
yield return(node);
foreach (char ch in node.Node.Children.Keys)
{
NodeWithText newNode = GenerateNodeWithText(node, ch);
wordsQueue.Enqueue(newNode);
}
}
}
