public static int[][] A_StarAlgorithm(int startRow, int startCol, int endRow, int endCol, int[][] graph)
{
List <List <Node> > nodes = initializeNodes(graph);
Node startNode = nodes[startRow][startCol];
Node endNode = nodes[endRow][endCol];
startNode.distanceFromStart = 0;
startNode.estimatedDistanceToEnd = calculateManhattanDistance(startNode, endNode);
List <Node> nodesToVisitList = new List <Node>();
nodesToVisitList.Add(startNode);
MinHeap nodesToVisit = new MinHeap(nodesToVisitList);
while (!nodesToVisit.isEmpty())
{
Node currentMinDistanceNode = nodesToVisit.Remove();
if (currentMinDistanceNode == endNode)
{
break;
}
List <Node> neighbors = getNeighboringNodes(currentMinDistanceNode, nodes);
foreach (var neighbor in neighbors)
{
if (neighbor.val == 1)
{
continue;
}
int tentativeDistanceToNeighbor = currentMinDistanceNode.distanceFromStart + 1;
if (tentativeDistanceToNeighbor >= neighbor.distanceFromStart)
{
continue;
}
neighbor.nodeCameFrom = currentMinDistanceNode;
neighbor.distanceFromStart = tentativeDistanceToNeighbor;
neighbor.estimatedDistanceToEnd = neighbor.distanceFromStart + calculateManhattanDistance(neighbor, endNode);
if (!nodesToVisit.ContainsNode(neighbor))
{
nodesToVisit.Insert(neighbor);
}
else
{
nodesToVisit.Update(neighbor);
}
}
}
return(retrieveShortestPath(endNode));
}