private IEnumerable <object> Day1(List <string> map)
{
HashSet <string> part2 = new HashSet <string>();
var start = new TileDay13();
start.Y = map.FindIndex(x => x.Contains("A"));
start.X = map[start.Y].IndexOf("A");
var finish = new TileDay13();
finish.Y = map.FindIndex(x => x.Contains("B"));
finish.X = map[finish.Y].IndexOf("B");
start.SetDistance(finish.X, finish.Y);
var activeTiles = new List <TileDay13>();
activeTiles.Add(start);
var visitedTiles = new List <TileDay13>();
while (true)
{
var checkTile = activeTiles.OrderBy(x => x.CostDistance).First();
if (checkTile.X == finish.X && checkTile.Y == finish.Y)
{
if (checkTile.Cost < 50)
{
part2.Add($"{checkTile.X}-{checkTile.Y}");
}
//We found the destination and we can be sure (Because the the OrderBy above)
//That it's the most low cost option.
var tile = checkTile;
//Console.WriteLine("Retracing steps backwards...");
while (true)
{
//Console.WriteLine($"{tile.X} : {tile.Y}");
if (map[tile.Y][tile.X] == '.')
{
var newMapRow = map[tile.Y].ToCharArray();
newMapRow[tile.X] = 'O';
map[tile.Y] = new string(newMapRow);
}
tile = tile.Parent;
if (tile == null)
{
//Console.WriteLine();
//map.ForEach(x => Console.WriteLine(x));
//Console.WriteLine();
yield return(checkTile.Cost);
}
}
}
visitedTiles.Add(checkTile);
activeTiles.Remove(checkTile);
var walkableTiles = GetWalkableTiles(map, checkTile, finish);
foreach (var walkableTile in walkableTiles)
{
//We have already visited this tile so we don't need to do so again!
if (visitedTiles.Any(x => x.X == walkableTile.X && x.Y == walkableTile.Y))
{
continue;
}
//It's already in the active list, but that's OK, maybe this new tile has a better value (e.g. We might zigzag earlier but this is now straighter).
if (activeTiles.Any(x => x.X == walkableTile.X && x.Y == walkableTile.Y))
{
var existingTile = activeTiles.First(x => x.X == walkableTile.X && x.Y == walkableTile.Y);
if (existingTile.CostDistance > checkTile.CostDistance)
{
activeTiles.Remove(existingTile);
activeTiles.Add(walkableTile);
}
}
else
{
//We've never seen this tile before so add it to the list.
activeTiles.Add(walkableTile);
}
}
}
//Console.WriteLine("No Path Found!");
//yield return $"";
}
private IEnumerable <object> Day2(List <string> map)
{
HashSet <string> part2 = new HashSet <string>();
//map.ForEach(a => Console.WriteLine(a));
var start = new TileDay13();
start.Y = map.FindIndex(x => x.Contains("A"));
start.X = map[start.Y].IndexOf("A");
var finish = new TileDay13();
finish.Y = map.FindIndex(x => x.Contains("B"));
finish.X = map[finish.Y].IndexOf("B");
start.SetDistance(finish.X, finish.Y);
var activeTiles = new List <TileDay13>();
activeTiles.Add(start);
var visitedTiles = new List <TileDay13>();
bool MoreTiles = true;
while (MoreTiles)
{
var checkTile = activeTiles.OrderBy(x => x.CostDistance).First();
if (checkTile.Cost < 50)
{
part2.Add($"{checkTile.X}-{checkTile.Y}");
}
yield return(part2.Count() + 1);
visitedTiles.Add(checkTile);
activeTiles.Remove(checkTile);
var walkableTiles = GetWalkableTiles(map, checkTile, finish);
foreach (var walkableTile in walkableTiles)
{
//We have already visited this tile so we don't need to do so again!
if (visitedTiles.Any(x => x.X == walkableTile.X && x.Y == walkableTile.Y))
{
continue;
}
//It's already in the active list, but that's OK, maybe this new tile has a better value (e.g. We might zigzag earlier but this is now straighter).
if (activeTiles.Any(x => x.X == walkableTile.X && x.Y == walkableTile.Y))
{
var existingTile = activeTiles.First(x => x.X == walkableTile.X && x.Y == walkableTile.Y);
if (existingTile.CostDistance > checkTile.CostDistance)
{
activeTiles.Remove(existingTile);
activeTiles.Add(walkableTile);
}
}
else
{
//We've never seen this tile before so add it to the list.
activeTiles.Add(walkableTile);
}
}
if (activeTiles.Count() == 0)
{
MoreTiles = false;
}
}
}
