public string Build(IList<MoveType> moves, out int score)
{
if(moves.Count == 0)
{
score = 0;
return string.Empty;
}
var scores = new Score[moves.Count];
var phrases = new string[moves.Count];
for(int idx = 0; idx < moves.Count; idx++)
{
var items = PowerPhrases
.Where(phrase => EndsWithPhrase(moves, phrase, idx))
.Select(phrase => new {Phrase = phrase, Score = idx < phrase.Length ? new Score() : scores[idx - phrase.Length]});
if(idx > 0)
items = items.Concat(new[] {new {Phrase = (string)null, Score = scores[idx - 1]}});
var item = items
.MaxOrDefault(elem => elem.Score.CountNewScore(elem.Phrase));
scores[idx] = item == null ? (idx == 0 ? new Score() : scores[idx - 1]) : item.Score.GetUpdatedScore(item.Phrase);
phrases[idx] = item == null ? null : item.Phrase;
}
score = scores[moves.Count - 1].TotalScore;
var result = new string[moves.Count];
for(int idx = moves.Count - 1; idx >= 0;)
{
var phrase = phrases[idx];
if(phrase != null)
{
result[idx] = phrase;
idx -= phrase.Length;
continue;
}
result[idx] = SelectMove(moves[idx]).First().ToString();
idx--;
}
return string.Join(null, result);
}
public Score GetUpdatedScore(string phrase)
{
var score = new Score
{
PhraseCounts = PhraseCounts == null ? new Dictionary<string, int>() : new Dictionary<string, int>(PhraseCounts),
TotalScore = CountNewScore(phrase)
};
if(phrase != null)
{
if(!score.PhraseCounts.ContainsKey(phrase))
score.PhraseCounts[phrase] = 0;
score.PhraseCounts[phrase]++;
}
return score;
}