/// <summary>
/// Return existing words changing only one letter
/// </summary>
/// <param name="sOldString">Initial string</param>
/// <returns></returns>
private static List<string> GetNewStrings(string sWord, WordDictionary dicc)
{
List<string> listNewStrings = new List<string>();
if (string.IsNullOrEmpty(sWord))
{
sWord = string.Empty;
}
if (dicc != null)
{
for (int i = 0; i < sWord.Length; i++)
{
char letter = sWord.ToLower()[i];
for (char l = 'a'; l <= 'z'; l++)
{
if (l == sWord[i]) continue;
StringBuilder sNewWord = new StringBuilder(sWord);
sNewWord[i] = l;
if (dicc.Contains(sNewWord.ToString()))
{
listNewStrings.Add(sNewWord.ToString());
}
}
}
}
return listNewStrings;
}
/// <summary>
/// Get a list of words given a secuence of phone keyboards numbers
/// </summary>
/// <param name="listNumber"></param>
/// <returns></returns>
public static List<string> GetWords(List<int> listNumber)
{
List<string> listWords = new List<string>();
// Validate input
if (listNumber == null || listNumber.Count == 0)
{
throw new ArgumentNullException("listNumber", "List null or empty");
}
if (listNumber.Exists (p=> p < 2 || p > 9))
{
throw new ArgumentOutOfRangeException("listNumber", "Numbers must be in range 2 - 9");
}
// Initialize queue
Queue<string> queue = new Queue<string>();
foreach (string s in GetNewStrings(string.Empty, listNumber[0]))
{
queue.Enqueue(s);
}
// Generate possible words
for (int i=1; i<listNumber.Count; i++)
{
while (queue.Count > 0 && queue.Peek().Count() <= i)
{
foreach (string s in GetNewStrings(queue.Dequeue(), listNumber[i]))
{
queue.Enqueue(s);
}
}
}
// Check possible words with a dictionary
WordDictionary dicc = new WordDictionary();
while (queue.Count > 0)
{
string sAux = queue.Dequeue();
if (dicc.Contains(sAux))
{
listWords.Add(sAux);
}
// Add all words generate
// listWords.Add(queue.Dequeue());
}
return listWords;
}