public void FlipTestTopOnly(string input, string expectedHash)
{
var pancakeStack = new PancakeStack(input);
var newPancakeStack = PancakeFlipper.Flip(1, pancakeStack);
Assert.AreEqual(expectedHash, newPancakeStack.GetHash());
Assert.AreEqual(1, newPancakeStack.Depth);
}
public PancakeStack FindOptimalStack(IEnumerable <PancakeStack> stacks)
{
var pancakeStacks = stacks as PancakeStack[] ?? stacks.ToArray();
logger.Debug("Evaluating {0} stacks", pancakeStacks.Length);
// Reach end of recursion if there are no more options to check
if (!pancakeStacks.Any())
{
return(null);
}
var NextStacksToCheck = new List <PancakeStack>();
// Return any if we are ready
var minPartiontion = pancakeStacks[0].Stack.Length;
foreach (var pancakeStack in pancakeStacks.OrderBy(x => x.GetPartitions()))
{
if (pancakeStack.ReadyToServe())
{
logger.Debug("Found best stack, {0} optimal flips, Orderd {1}", pancakeStack.Depth, pancakeStack.FlipOrder);
return(pancakeStack);
}
if (pancakeStack.GetPartitions() < minPartiontion)
{
minPartiontion = pancakeStack.GetPartitions();
}
}
logger.Debug("Minimum partions is {0}", minPartiontion);
// Not Good stack, so let's start flipping each stack we have that is a step in the correct direction
foreach (var pancakeStack in pancakeStacks.Where(x => x.GetPartitions() == minPartiontion))
{
// Keeping track of stacks that have already generated children stacks
Hashes.Add(pancakeStack.GetHash());
// Flip all possible ways
for (var i = 1; i <= pancakeStack.Stack.Length; i++)
{
var flippedStack = PancakeFlipper.Flip(i, pancakeStack);
// More Entropy probably means we aren't going in the right direction
if (flippedStack.GetPartitions() > pancakeStack.GetPartitions())
{
continue;
}
// If this is the first time we see the stack, we'll check out all it's options
if (!Hashes.Contains(flippedStack.GetHash()))
{
NextStacksToCheck.Add(flippedStack);
break;
}
}
}
return(FindOptimalStack(NextStacksToCheck));
}
