private string BestStringSplit(Hashtable ht, string sentence)
{
//We can use ht as memo or array of ParseResult object
Dictionary <int, ParseResult1> memo = new Dictionary <int, ParseResult1>();
ParseResult1 r = Split(ht, sentence, 0, memo);
return(r == null ? null : r.Parsed);
}
private ParseResult1 Split(Hashtable ht, string sentence, int index, Dictionary <int, ParseResult1> memo)
{
if (index >= sentence.Length)
{
return(new ParseResult1(0, string.Empty));
}
if (memo.ContainsKey(index))
{
return(memo[index]);
}
int bestInvalid = Int32.MaxValue;
string bestparsing = null;
string partial = "";
int startindex = index;
while (startindex < sentence.Length)
{
char c = sentence[startindex];
partial += c;
int invalid = ht.ContainsKey(partial) ? 0 : partial.Length;
if (invalid < bestInvalid)
{
ParseResult1 result = Split(ht, sentence, startindex + 1, memo);
if (invalid + result.NoOfInvalidCharacters < bestInvalid)
{
bestInvalid = invalid + result.NoOfInvalidCharacters;
bestparsing = partial + " " + result.Parsed;
if (bestInvalid == 0)
{
break;
}
}
}
//This is important step..increment the index to see every possible prefix starting from this index can make best split
startindex++;
}
ParseResult1 indexbestparse = new ParseResult1(bestInvalid, bestparsing);
memo.Add(index, indexbestparse);
return(indexbestparse);
}