private static int BFSLevels(PositionsGraph <Position> positions, Position start)
{
int count = 0;
Queue <Position> toVisit = new Queue <Position>();
Queue <Position> childrenQueue = new Queue <Position>();
var positionsVisited = new List <Position>();
toVisit.Enqueue(start);
while (positions.AdjacencyList.Count != positionsVisited.Count)
{
while (toVisit.Count > 0)
{
var currentNode = toVisit.Dequeue();
positionsVisited.Add(currentNode);
var children = positions.AdjacencyList[currentNode];
foreach (var child in children)
{
if (!positionsVisited.Any(pos => pos.X == child.X && pos.Y == child.Y))
{
childrenQueue.Enqueue(child);
}
}
}
count++;
toVisit = new Queue <Position>(childrenQueue);
childrenQueue.Clear();
}
return(count - 1);
}
public static int Part2Solution(long[] input)
{
PositionsGraph <Position> positions = new PositionsGraph <Position>();
var levelsReached = new List <int>();
DFSGrid(input, positions);
return(BFSLevels(positions, positions.AdjacencyList.First(x => x.Key.HasOxygen).Key));
}
public static long Part1Solution(long[] input)
{
PositionsGraph <Position> positions = new PositionsGraph <Position>();
return(DFSGrid(input, positions));
}
private static long DFSGrid(long[] input, PositionsGraph <Position> positions)
{
Droid droid = new Droid(new IntCodeProgram(input));
Position currentPosition = new Position(0, 0, Answer.Allowed);
positions.AddVertex(currentPosition);
Stack <Command> currentCommands = new Stack <Command>();
long currentDistance = 0;
while (true)
{
bool foundDeadEnd = false;
Console.WriteLine($"I'm at current position {currentPosition.X}:{currentPosition.Y}");
Command command = CommandToTry(currentPosition);
if (command == Command.NoCommand)
{
Console.WriteLine($"Found dead end {currentPosition.X}:{currentPosition.Y}");
command = GetOpposite(currentCommands.Pop());
foundDeadEnd = true;
currentDistance--;
}
else
{
currentCommands.Push(command);
currentDistance++;
}
var nextPosition = new Position(currentPosition.X, currentPosition.Y, Answer.Allowed);
Console.WriteLine($"Going to go {command.ToString()}");
switch (command)
{
case Command.North:
nextPosition.Y++;
nextPosition.SouthTried = true;
currentPosition.NorthTried = true;
break;
case Command.South:
nextPosition.Y--;
nextPosition.NorthTried = true;
currentPosition.SouthTried = true;
break;
case Command.West:
nextPosition.X--;
nextPosition.EastTried = true;
currentPosition.WestTried = true;
break;
case Command.East:
nextPosition.X++;
nextPosition.WestTried = true;
currentPosition.EastTried = true;
break;
case Command.NoCommand:
throw new Exception("No Command passed through");
}
Answer answer = droid.Move(command);
switch (answer)
{
case Answer.Wall:
if (!foundDeadEnd)
{
currentCommands.Pop();
}
Console.WriteLine("Hit a wall");
break;
case Answer.Allowed:
if (!positions.ContainsVertex(nextPosition))
{
positions.AddVertex(nextPosition);
positions.AddEdge(Tuple.Create(currentPosition, nextPosition));
}
nextPosition = positions.GetVertex(nextPosition).Key;
Console.WriteLine($"Moved from {currentPosition.X}:{currentPosition.Y} to {nextPosition.X}:{nextPosition.Y}");
nextPosition.Distance = currentCommands.Count;
currentPosition = nextPosition;
break;
case Answer.Success:
if (!positions.ContainsVertex(nextPosition))
{
positions.AddVertex(nextPosition);
positions.AddEdge(Tuple.Create(currentPosition, nextPosition));
}
nextPosition = positions.GetVertex(nextPosition).Key;
Console.WriteLine($"Moved from {currentPosition.X}:{currentPosition.Y} to {nextPosition.X}:{nextPosition.Y} OXYGEN");
nextPosition.HasOxygen = true;
nextPosition.Distance = currentCommands.Count;
currentPosition = nextPosition;
break;
}
Console.WriteLine($"I still have {currentCommands.Count} commands on the queue");
if (currentCommands.Count == 0 && positions.AdjacencyList.All(x => x.Key.EastTried && x.Key.NorthTried && x.Key.SouthTried && x.Key.WestTried))
{
return(positions.AdjacencyList.First(x => x.Key.HasOxygen).Key.Distance);
}
}
}
