public float Score(FastWorld w, int ownIndex, Util.FillResult fill)
{
int maxLength = 0;
int sumLength = 0;
int otherCount = 0;
for (int i = 0; i < w.Snakes.Count; ++i)
{
if (i == ownIndex)
{
continue;
}
if (!w.Snakes[i].Alive)
{
continue;
}
sumLength += w.Snakes[i].Length;
otherCount += 1;
if (w.Snakes[i].Length > maxLength)
{
maxLength = w.Snakes[i].Length;
}
}
float averageLength = sumLength / (float)otherCount;
float interpLength = 0.9f * maxLength + 0.1f * averageLength;
float deltaAdvantage = w.Snakes[ownIndex].Length - interpLength;
float deltaMetric = ScoreDeltaAdvantage(deltaAdvantage);
float deltaOnEatMetric = ScoreDeltaAdvantage(deltaAdvantage + 1);
// If food distance metric is 1, want to be exactly as good as eating one
// fruit. Since food distance metric is always less than 1, ensures that eating
// is always better than guarding with proximity of 1.
float foodMetricMultiplier = (deltaOnEatMetric - deltaMetric) * FruitMultiplierFactor;
float score = deltaMetric + FoodDistanceMetric(w, ownIndex, fill) * foodMetricMultiplier;
Debug.Assert(!float.IsNaN(score));
return(score);
}
private float FoodDistanceMetric(FastWorld w, int ownIndex, Util.FillResult fill)
{
int bestOwnDistance = int.MaxValue;
foreach (var fruit in w.Fruits)
{
var dist = fill.Distances[fruit.Y, fruit.X];
if (dist <= 0)
{
continue;
}
bestOwnDistance = Math.Min(bestOwnDistance, dist);
}
if (bestOwnDistance == int.MaxValue)
{
return(0);
}
return((float)Math.Exp(-FoodDistanceDecay * bestOwnDistance));
}
