private IEnumerable <int> FindMoves(int state)
{
var(x, y, j, p) = NavigationUtils.DecodeState(state);
foreach (var findWalkMove in FindWalkMoves(x, y, j, p))
{
yield return(findWalkMove);
}
foreach (var findUsualFlyUpMove in FindUsualFlyUpMoves(x, y, j, p))
{
yield return(findUsualFlyUpMove);
}
foreach (var findUsualFlyDownMove in FindUsualFlyDownMoves(x, y, j, p))
{
yield return(findUsualFlyDownMove);
}
}
public List <int> FindPath(int s, int fx, int fy, int dist = 0)
{
if (_lastPath != null && fx == _lastFx && fy == _lastFy && _lastPath.Count > 0)
{
var(sx, sy, jj, pp) = NavigationUtils.DecodeState(s);
var(sx1, sy1, jj1, pp1) = NavigationUtils.DecodeState(_lastPath[0]);
if (sx == sx1 && sy == sy1)
{
_lastPath.RemoveAt(0);
return(_lastPath);
}
}
var order = new LinkedList <int>();
order.AddLast(s);
var parent = new Dictionary <int, int>();
parent.Add(s, s);
int f = -1;
while (order.Count > 0)
{
var currentCode = order.First.Value;
order.RemoveFirst();
var(x, y, j, p) = NavigationUtils.DecodeState(currentCode);
if (Math.Abs(x - fx) <= dist && Math.Abs(y - fy) <= dist)
{
f = currentCode;
break;
}
var currentPoint = NavigationUtils.EncodePoint(x, y);
for (int move = 0; move < PointMaster.Moves; ++move)
{
if (!_pointMaster.IsValidMove(currentPoint, move))
{
continue;
}
var newCode = ApplyMove(x, y, j, p, move);
if (newCode < 0 || parent.ContainsKey(newCode))
{
continue;
}
var(nx, ny, nj, np) = NavigationUtils.DecodeState(newCode);
parent[newCode] = currentCode;
order.AddLast(newCode);
}
if (j == 1 && p == 1)
{
var newCode = NavigationUtils.EncodeState(x, y, 0, 0);
if (newCode < 0 || parent.ContainsKey(newCode))
{
continue;
}
parent[newCode] = currentCode;
order.AddLast(newCode);
}
}
if (f == -1)
{
return(null);
}
var path = new List <int>();
var cur = f;
while (cur != s)
{
cur = parent[cur];
if (cur == s)
{
break;
}
path.Add(cur);
}
path.Reverse();
order.Clear();
parent.Clear();
_lastFx = fx;
_lastFy = fy;
_lastPath = path;
return(path);
}
