public Day20Room GetRoom(char direction)
{
switch (direction)
{
case 'W':
return(west ?? (west = new Day20Room {
east = this
}));
case 'E':
return(east ?? (east = new Day20Room {
west = this
}));
case 'N':
return(north ?? (north = new Day20Room {
south = this
}));
case 'S':
return(south ?? (south = new Day20Room {
north = this
}));
}
throw new Exception("Unkonwn direction!");
}
public static Day20Room CreateMap(string input)
{
input = new string(input.SkipWhile(x => x.Equals('^')).TakeWhile(x => x != '$').ToArray());
var startRoom = new Day20Room();
Process(input, new List <Day20Room> {
startRoom
});
startRoom.CalculateDistances();
return(startRoom);
List <Day20Room> Process(string a, List <Day20Room> inputRooms)
{
List <Day20Room> resultingRooms = new List <Day20Room>();
List <Day20Room> currentRooms = inputRooms.ToList();
for (int i = 0; i < a.Length; i++)
{
var character = a[i];
switch (character)
{
case '(':
int count = 1;
var sb = new StringBuilder();
while (count != 0)
{
i++;
if (a[i] == '(')
{
count++;
}
else if (a[i] == ')')
{
count--;
}
sb.Append(a[i]);
}
resultingRooms.Clear();
var next = sb.ToString();
currentRooms = Process(next.Substring(0, next.Length - 1), currentRooms);
break;
case '|':
resultingRooms.AddRange(currentRooms);
currentRooms = inputRooms.ToList();
break;
case ')':
throw new Exception("Unexcepted input. Maybe mismatched parentheses?");
default:
currentRooms = currentRooms.Select(x => x.GetRoom(character)).ToList();
break;
}
}
return(resultingRooms.Distinct().ToList());
}
}