/// <summary>
/// 获取当前站点的下一个可直达特殊点
/// </summary>
private HashSet <Station> GetNexts(Station current, Station start)
{
HashSet <Station> nexts = new HashSet <Station>();
foreach (int i in current.PassLineIds)
{
MetroLine line = _metro.MetroLines.Find((MetroLine l) => l.Id == i);
int currentPosition = line.Stations.IndexOf(current);
HashSet <int> specialPositionsSet = new HashSet <int>();
specialPositionsSet.Add(0);
specialPositionsSet.Add(line.Stations.Count - 1);
if (line.Stations.Contains(start))
{
specialPositionsSet.Add(line.Stations.IndexOf(start));
}
foreach (Station s in line.GetTransferStations())
{
specialPositionsSet.Add(line.Stations.IndexOf(s));
}
specialPositionsSet.Add(line.Stations.IndexOf(current));
// 排序
List <int> specialPositions = new List <int>(specialPositionsSet);
specialPositions.Sort((a, b) => a > b ? 1 : -1);
// 寻找下一个可达特殊点
for (int j = 0; j < specialPositions.Count; j++)
{
if (j == 0)
{
if (currentPosition == specialPositions[j] && j + 1 <= specialPositions.Count - 1)
{
nexts.Add(line.Stations[specialPositions[j + 1]]);
}
}
else if (j == specialPositions.Count - 1)
{
if (currentPosition == specialPositions[j] && j - 1 >= 0)
{
nexts.Add(line.Stations[specialPositions[j - 1]]);
}
}
else if (currentPosition > specialPositions[j - 1])
{
if (currentPosition == specialPositions[j])
{
nexts.Add(line.Stations[specialPositions[j - 1]]);
nexts.Add(line.Stations[specialPositions[j + 1]]);
}
else if (currentPosition < specialPositions[j])
{
nexts.Add(line.Stations[specialPositions[j - 1]]);
nexts.Add(line.Stations[specialPositions[j]]);
}
}
}
}
return(nexts);
}
// 两点之间寻路递归算法
private void FindPath(List <Path> result, int startLine, int endLine, Station startStation, Station endStation,
List <Station> list, List <int> alreadyPassLines)
{
if (alreadyPassLines == null)
{
alreadyPassLines = new List <int>();
}
if (startStation.Id == endStation.Id)
{
return;
}
// 到同一路线上了，将结果加到list中
if (startLine == endLine)
{
List <Station> temp = GetPathBetween(startStation, endStation, startLine);
// 最后一次使用list了，直接用
if (list == null) // 为null表示一开始就是同路，直接赋值
{
list = temp;
}
else // 不为null表示之前有换线前的数据，在末尾添加
{
foreach (Station s in temp)
{
list.Add(s);
}
}
list.Add(endStation);
result.Add(new Path(list, alreadyPassLines));
}
// 还没在同一条路线上，寻找下一个换乘点
alreadyPassLines.Add(startLine); // 当前路算已走过了，不要再回来了
MetroLine line = _metro.MetroLines.Find((MetroLine l) => { return(l.Id == startLine); });
foreach (Station s in line.GetTransferStations())
{
foreach (int i in s.PassLineIds)
{
if (!alreadyPassLines.Contains(i))
{
List <Station> path;
List <Station> temp = GetPathBetween(startStation, s, startLine);
// 因为每个循环都会用到之前的list，所以这里不能更改list，传变量path
if (list == null) // 为null表示第一次，直接赋值
{
path = temp;
}
else // 不为null表示之前有路径，添加到末尾
{
path = new List <Station>();
foreach (Station st in list)
{
path.Add(st);
}
foreach (Station st in temp)
{
path.Add(st);
}
}
List <int> tempAlreadyLines = new List <int>();
foreach (int j in alreadyPassLines)
{
tempAlreadyLines.Add(j);
}
FindPath(result, i, endLine, s, endStation, path, tempAlreadyLines); // 递归查找子路径
}
}
}
}