/// <summary>
/// 获得保证最小消耗的路径(需要访问所有节点)BFS
/// 时间复杂度：O(nlgn)
/// 空间复杂度 O(n)
/// </summary>
/// <param name="start"></param>
/// <param name="end"></param>
/// <param name="nodesMap"></param>
/// <returns></returns>
public static Queue <Node> FindWay(
Node start,
Node end,
Dictionary <Node, int> nodesMap
)
{
//Init
FindPathAlgorithm.Init(nodesMap);
//First Node
canGetMinNodelist.Add(start);
int curcount = 1;
CostDict[start] = 0;
RoadDict[start].Enqueue(start);
visit[start] = true;
curcount++;
//Find
while (curcount < NodeCount && canGetMinNodelist.Count > 0)
{
//查找访问过节点中距离终点最近的点
Node cur = (Node)GetMinNodeFromArr(canGetMinNodelist, end, x => H(x, end));
//查找cur所能到达的节点列表
List <Node> arr = GetNearbyNode(cur, false);
//遍历列表里的所有的节点
for (int i = 0; i < arr.Count; i++)
{
Node n = arr[i];
//设置为已访问
if (!visit[n])
{
canGetMinNodelist.Add(n);
visit[n] = true;
curcount++;
}
//如果新的路径更短，更新路径
int newcost = CostDict[cur] + NodesMap[n];
if (CostDict[n] > newcost)
{
CostDict[n] = newcost;
RoadDict[n] = new Queue <Node>(RoadDict[cur]);
RoadDict[n].Enqueue(n);
}
}
canGetMinNodelist.Remove(cur);
}
return(RoadDict[end]);
}
/// <summary>
/// 以距离为导向的寻路
/// </summary>
/// <param name="start"></param>
/// <param name="end"></param>
/// <param name="nodesMap"></param>
/// <returns></returns>
public static Queue <Node> FindWayGreedy(
Node start,
Node end,
Dictionary <Node, int> nodesMap
)
{
//Init
FindPathAlgorithm.Init(nodesMap);
//First Node
CostDict[start] = 0;
RoadDict[start].Enqueue(start);
Func <Node, int> GetMin = node => (int)(Math.Pow(node.x - end.x, 2) + Math.Pow(node.z - end.z, 2));
canGetMinNodelist.Add(start);
Node?curnode = null;
Node cur = start;
//Find
while (cur != end)
{
//查找访问过节点中距离终点最近的节点
curnode = GetMinNodeFromArr(canGetMinNodelist, end, GetMin);
//无法到达终点
if (null == curnode)
{
break;
}
//查找curnode下一个节点中距离终点最近的点
cur = (Node)curnode;
Node?minnode = GetMinNode(cur, end, GetMin);
if (null == minnode)
{
//当前节点无法到达终点
canGetMinNodelist.Remove(cur);
continue;
}
else
{
Node _min = (Node)minnode;
//标记为已访问
visit[_min] = true;
canGetMinNodelist.Add(_min);
//更新路径
CostDict[_min] = CostDict[cur] + NodesMap[_min];
RoadDict[_min].Clear();
foreach (var e in RoadDict[cur])
{
RoadDict[_min].Enqueue(e);
}
RoadDict[_min].Enqueue(_min);
}
}
return(RoadDict[end]);
}
