/// <summary>
/// Crawls this instance.
/// </summary>
/// <returns>The solution if found</returns>
/// <remarks>We have to override this so we can synchonize the forward and reverse crawlers</remarks>
public override BaseNode Crawl()
{
if (!this.reversed)
{
BaseNode solution = null;
while ((!this.IsQueueEmpty() || !reverseCrawler.IsQueueEmpty()) && solution == null)
{
this.EvaluateAndExpandNode(this.PopQueue());
reverseCrawler.Crawl();
// If there exists a node that both crawlers have found where, combined, a solution is found; that is our winner.
List <BaseNode> similarNodes = this.ExploredSet.Where(en => reverseCrawler.ExploredSet.Any(rcEn => rcEn.Key == en.Key)).ToList();
foreach (BaseNode similarNode in similarNodes)
{
foreach (BaseNode possibleSolution in this.reverseCrawler.ExploredSet.Where(en => en.Key == similarNode.Key))
{
List <Move> movesToGoal = TreeHelpers.ActionTracker(possibleSolution);
movesToGoal.Reverse();
movesToGoal = TreeHelpers.ReflectMoves(movesToGoal);
int x = similarNode.X;
int y = similarNode.Y;
List <int[]> newChildState = new List <int[]>();
similarNode.CrateLocations.ForEach(state => newChildState.Add(new int[] { state[0], state[1] }));
this.MoveToCurrentNode(movesToGoal, ref x, ref y, ref newChildState);
if (IsWinningState(newChildState))
{
return(InvertNodeHeritage(similarNode, possibleSolution.Parent));
}
}
}
}
return(solution);
}
else
{
// If we are the reversed solution, we just need to take the normal steps and return if we found a solution.
// all the Bi-Directional stuff is done in the non-reversed loop.
BaseNode reverseSolution;
reverseSolution = this.EvaluateAndExpandNode(this.PopQueue());
return(reverseSolution);
}
}
/// <summary>
/// Calculates the results.
/// </summary>
/// <param name="solution">The solution.</param>
/// <returns>The results of the exploration</returns>
private string[] CalculateResults(BaseNode solution)
{
if (solution == null)
{
return new[] { "Failure. No solution found." }
}
;
List <string> compiledFinalState = new List <string>();
string elapsedTime = this.ElapsedTime.ToString();
List <Move> movesToSolution = TreeHelpers.ActionTracker(solution);
string numberOfMoves = movesToSolution.Count.ToString();
string moveBreakdown = movesToSolution.Aggregate(string.Empty, (current, move) => current + move.ToString());
string prettyDims = this.mapDims[0] + " " + this.mapDims[1];
compiledFinalState.Add(elapsedTime);
compiledFinalState.Add(numberOfMoves);
compiledFinalState.Add(moveBreakdown);
compiledFinalState.Add(prettyDims);
compiledFinalState.Add(solution.Key);
// Put the crates in the map for display
foreach (int[] crate in solution.CrateLocations)
{
this.map[crate[0], crate[1]] = AlgorithmConstants.crate;
}
for (int row = 0; row < this.mapDims[1]; row++)
{
string temp = string.Empty;
for (int column = 0; column < this.mapDims[0]; column++)
{
temp += this.map[column, row];
}
compiledFinalState.Add(temp);
}
return(compiledFinalState.ToArray());
}
}