private BucketPuzzleSolveOutcome Solve(BucketPuzzle problem, int limit)
{
var frontier = new Stack <BucketPuzzle>();
frontier.Push(problem);
var explored = new List <BucketPuzzle>();
do
{
var candidate = frontier.Pop();
if (candidate.IsASolution)
{
return(BucketPuzzleSolveOutcome.Solution(candidate));
}
explored.Add(candidate);
var childStates = candidate.Expand(limit);
foreach (var childState in childStates)
{
if (!explored.Any(e => e.IsSame(childState)) &&
!frontier.Any(f => f.IsSame(childState)))
{
frontier.Push(childState);
}
}
} while (frontier.Count > 0);
return(BucketPuzzleSolveOutcome.CutOff(problem));
}
public bool IsSame(BucketPuzzle that)
{
var thisState = this.Buckets.Select(b => (b.Id, b.Volume, b.Capacity)).OrderBy(b => b.Id).ToList();
var thatState = that.Buckets.Select(b => (b.Id, b.Volume, b.Capacity)).OrderBy(b => b.Id).ToList();
var sequenceEqual = thisState.SequenceEqual(thatState);
return(sequenceEqual);
}
public BucketPuzzleSolveOutcome Solve(BucketPuzzle problem)
{
const int depthLimit = 256; // Give up after so many iterations.
for (var depth = 0; depth < depthLimit; depth++)
{
var outcome = this.Solve(problem, depth);
if (outcome.Classification != SolutionOutcomeClassification.CutOff)
{
return(outcome);
}
}
return(BucketPuzzleSolveOutcome.CutOff(problem));
}
private BucketPuzzle(IEnumerable <Bucket> buckets, bool canEmpty, bool canRefill, int targetVolume, int depth, BucketPuzzle parent, string action)
{
this.Buckets = buckets;
this.CanEmpty = canEmpty;
this.CanRefill = canRefill;
this.TargetVolume = targetVolume;
this.Depth = depth;
this.Parent = parent;
this.Action = action;
}