/// <summary>
/// Run one iteration of a dijkstra map update. Each cell is set to the lowest
/// adjacent value - 1.
/// </summary>
/// <param name="dMap"></param>
/// <param name="blockedValue"></param>
/// <returns></returns>
public static bool IterateDijkstraMap(this ICellMap <int> dMap, int blockedValue = -1)
{
bool changed = false;
for (int i = 0; i < dMap.CellCount; i++)
{
int cellValue = dMap[i];
if (cellValue != blockedValue)
{
int lowestValue = cellValue;
for (int ai = 0; ai <= dMap.AdjacencyCount(i); ai++)
{
int adjacentCellIndex = dMap.AdjacentCellIndex(i, ai);
if (dMap.Exists(adjacentCellIndex))
{
int adjacentValue = dMap[adjacentCellIndex];
if (adjacentValue < lowestValue)
{
lowestValue = adjacentValue;
}
}
}
if (lowestValue < cellValue - 1)
{
dMap[i] = lowestValue + 1;
changed = true;
}
}
}
return(changed);
}
/// <summary>
/// Retrieve a list of all cells adjacent to the one with the specified index
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="map"></param>
/// <param name="cellIndex"></param>
/// <returns></returns>
public static IList <T> AdjacentCells <T>(this ICellMap <T> map, int cellIndex)
{
int aC = map.AdjacencyCount(cellIndex);
var result = new List <T>(aC);
for (int i = 0; i < aC; i++)
{
int iA = map.AdjacentCellIndex(cellIndex, i);
if (map.Exists(iA))
{
result.Add(map[iA]);
}
}
return(result);
}