protected byte[,] CalcItineraryMatrix(int num)
{
var boxSize = (_game.Version == 0) ? num : 64;
// Allocate the adjacent & itinerary matrices
var itineraryMatrix = new byte[boxSize, boxSize];
var adjacentMatrix = new byte[boxSize, boxSize];
// Initialize the adjacent matrix: each box has distance 0 to itself,
// and distance 1 to its direct neighbors. Initially, it has distance
// 255 (= infinity) to all other boxes.
for (byte i = 0; i < num; i++)
{
for (byte j = 0; j < num; j++)
{
if (i == j)
{
adjacentMatrix[i, j] = 0;
itineraryMatrix[i, j] = j;
}
else if (AreBoxesNeighbors(i, j))
{
adjacentMatrix[i, j] = 1;
itineraryMatrix[i, j] = j;
}
else
{
adjacentMatrix[i, j] = 255;
itineraryMatrix[i, j] = InvalidBox;
}
}
}
// Compute the shortest routes between boxes via Kleene's algorithm.
// The original code used some kind of mangled Dijkstra's algorithm;
// while that might in theory be slightly faster, it was
// a) extremly obfuscated
// b) incorrect: it didn't always find the shortest paths
// c) not any faster in reality for our sparse & small adjacent matrices
for (byte k = 0; k < num; k++)
{
for (byte i = 0; i < num; i++)
{
for (byte j = 0; j < num; j++)
{
if (i == j)
continue;
byte distIK = adjacentMatrix[i, k];
byte distKJ = adjacentMatrix[k, j];
if (adjacentMatrix[i, j] > distIK + distKJ)
{
adjacentMatrix[i, j] = (byte)(distIK + distKJ);
itineraryMatrix[i, j] = itineraryMatrix[i, k];
}
}
}
}
return itineraryMatrix;
}
