几个有关图的算法2(DFS,TopoLogicalSort) .

深度优先算法和拓扑算法是很多算法的基础,只得深究:

/// <summary>    /// 广度搜索算法,图    /// </summary>    public partial class GraphicSearchAlg    {              /// <summary>        /// 深度优先搜索算法,这里只是计算深度.        /// </summary>        /// <param name="g">图,基于邻接表示</param>        /// <param name="s">源点</param>        public void DFS(Graphic g, Node s)        {            g.FinishOrder = 0;            g.EnterOrder = 0;            //初始化            foreach (var theNode in g.Nodes)            {                theNode.VisitedSign = 0;//0 white,1 gray,2 black                theNode.Parent = null;                theNode.EnterTime = 0;                theNode.FinishTime = 0;                theNode.FinishOrder = 0;                theNode.EnterOrder = 0;            }            s.VisitedSign = 1;            int theVisitTime = 0;            DFS_Visit(g, s, ref theVisitTime);            foreach (var theNode in g.Nodes)            {                if (theNode.VisitedSign == 0)                {                    DFS_Visit(g, theNode, ref theVisitTime);                }            }                    }        /// <summary>        /// DFS访问算法.        /// </summary>        /// <param name="g"></param>        /// <param name="u"></param>        /// <param name="VisitTime"></param>        private void DFS_Visit(Graphic g, Node u,ref int VisitTime)        {            u.VisitedSign = 1;            VisitTime++;            u.EnterTime = VisitTime;            g.EnterOrder++;            u.EnterOrder = g.EnterOrder;                        foreach (var theAdjNode in u.AdjNodes.Keys)            {                //边分类,存放在对应边的value值.0树边，1 方向边, 2正向边,3交叉边.                 switch (theAdjNode.VisitedSign)                {                    case 1:                        u.AdjNodes[theAdjNode].EdgeType = 1;                        break;                    case 2:                        if (u.EnterTime < theAdjNode.EnterTime)                        {                            u.AdjNodes[theAdjNode].EdgeType = 2;                        }                        else                        {                            u.AdjNodes[theAdjNode].EdgeType = 3;                        }                        break;                    default:                        u.AdjNodes[theAdjNode].EdgeType = 0;                        break;                }                if (theAdjNode.VisitedSign == 0)                {                    theAdjNode.Parent = u;                    DFS_Visit(g, theAdjNode, ref VisitTime);                }            }            u.VisitedSign = 2;            VisitTime++;            u.FinishTime = VisitTime;            g.FinishOrder++;            u.FinishOrder = g.FinishOrder;        }       /// <summary>       /// 拓扑排序       /// </summary>       /// <param name="g">有限无回路图</param>       /// <returns></returns>        public Node[] TopoLogicalSort(Graphic g)        {            int theLen = g.Nodes.Count;            Node[] theLink = new Node[theLen];            DFS(g, g.Nodes[0]);            foreach (var theNode in g.Nodes)            {                theLink[theLen - theNode.FinishOrder] = theNode;            }            return theLink.ToArray();        }    }