• 重新整理数据结构与算法(c#)—— 图的深度遍历和广度遍历[十一]


    参考网址:https://www.cnblogs.com/aoximin/p/13162635.html

    前言

    简介图:

    在数据的逻辑结构D=(KR)中,如果K中结点对于关系R的前趋和后继的个数不加限制,即仅含一种任意的关系,则称这种数据结构为图形结构。

    来源百度百科

    图形结构是一种比树形结构更复杂的非线性结构。在树形结构中,结点间具有分支层次关系,每一层上的结点只能和上一层中的至多一个结点相关,但可能和下一层的多个结点相关。而在图形结构中,任意两个结点之间都可能相关,即结点之间的邻接关系可以是任意的

    然后就是盗图阶段:

    后面就是一些基础常识,我找到一个比较全的:

    https://www.cnblogs.com/songgj/p/9107797.html

    正文

    那么就来看一下图的深度遍历和广度遍历吧。

    先来定义一个图:

    public class Graph
    {
    	private List<String> vertexList; //存储顶点集合
    	private int[,] edges; //存储图对应的邻结矩阵
    	private Boolean[] isVisited;// 判断是否访问了
    	int numOfEdges;
    	public Graph(int n){
    		vertexList = new List<string>();
    		edges = new int[8, 8];
    		isVisited = new Boolean[8];
    	}
    	/// <summary>
    	/// 增加节点
    	/// </summary>
    	/// <param name="vertex">节点</param>
    	public void addVertex(string vertex)
    	{
    		vertexList.Add(vertex);
    	}
    	public void insertEdge(int x,int y,int weight)
    	{
    		//增加他们的连线 且设置他们的权重
    		edges[x, y] = 1;
    		edges[y, x] = 1;
    		numOfEdges++;
    	}
    
    	public void showEdges()
    	{
    		for (int i=0;i< isVisited.Length;i++)
    		{
    			for (int j = 0; j < isVisited.Length; j++)
    			{
    				Console.Write(edges[i,j]+"  ");
    			}
    			Console.WriteLine();
    		}
    	}
    }
    

    测试一下:

    String[] Vertexs = { "1", "2", "3", "4", "5", "6", "7", "8" };
    //创建图对象
    Graph graph = new Graph(Vertexs.Count());
    //循环的添加顶点
    foreach (String vertex in Vertexs)
    {
    	graph.addVertex(vertex);
    }
    //更新边的关系
    graph.insertEdge(0, 1, 1);
    graph.insertEdge(0, 2, 1);
    graph.insertEdge(1, 3, 1);
    graph.insertEdge(1, 4, 1);
    graph.insertEdge(3, 7, 1);
    graph.insertEdge(4, 7, 1);
    graph.insertEdge(2, 5, 1);
    graph.insertEdge(2, 6, 1);
    graph.insertEdge(5, 6, 1);
    graph.showEdges();
    Console.ReadKey();
    

    结果:

    这么看可能不清晰哈,那么我画个图,看一下。

    这是下面这张图哈:

    深度遍历:

    private int getFirstNeighbor(int index)
    {
    	for (int j = 0; j < isVisited.Length; j++)
    	{
    		if (edges[index, j] > 0)
    		{
    			return j;
    		}
    	}
    	return -1;
    }
    /// <summary>
    /// 通过邻接节点来获取下一个节点
    /// </summary>
    /// <param name="v1"></param>
    /// <param name="v2"></param>
    /// <returns></returns>
    public int getNextNeighbor(int v1, int v2)
    {
    	for (int j = v2+1; j < isVisited.Length; j++)
    	{
    		if (edges[v1, j] > 0)
    		{
    			return j;
    		}
    	}
    	return -1;
    }
    /// <summary>
    /// 深度遍历
    /// </summary>
    /// <param name="i"></param>
    public void dfs(int i)
    {
    	//打印遍历的值
    	Console.Write(vertexList[i]+"  ");
    	isVisited[i] = true;
    	int w = getFirstNeighbor(i);
    	while (w != -1)
    	{
    		if (!isVisited[w])
    		{
    			dfs(w);
    		}
    		w = getNextNeighbor(i,w);
    	}
    }
    

    然后调用函数:

     graph.dfs(0);
    

    得到的结果是:

    看下广度遍历吧:

    //对一个结点进行广度优先遍历的方法
    public void bfs(int i)
    {
    	//打印遍历的值
    	Console.Write(vertexList[i] + "  ");
    	LinkedList<int> queue = new LinkedList<int>();
    	queue.AddLast(i);
    	int u;
    	while (queue.Count != 0)
    	{
    		u = queue.First.Value;
    		queue.RemoveFirst();
    		int w = getFirstNeighbor(i);
    		while (w != -1)
    		{
    			if (!isVisited[w])
    			{
    				Console.Write(vertexList[w] + "  ");
    				isVisited[w] = true;
    				queue.AddLast(w);
    			}
    			w = getNextNeighbor(u, w);
    		}
    	}
    }
    

    然后调用:

    Console.WriteLine("广度遍历");
    graph.bfs(0);
    

    结果:

    //自己编写的代码 仅供参考

      public class Node<T>

        {

            public bool accessed = false;

            public T t;

        }

        public class MyGrapic<T>

        {

            private Node<T>[] arryNode = null;

            private int[,] Matrix = null;

            private int num;

            public MyGrapic(Node<T>[] arrn)

            {

                arryNode = arrn;

                var n = arrn.Length;

                Matrix = new int[n, n];

                this.num = n;

                this.initMatix();

            }

            private void initMatix()

            {

                for (int i = 0; i < this.num; i++)

                {

                    for (int j = 0; i < this.num; i++)

                    {

                        Matrix[i, j] = 0;

                    }

                }

            }

            public void SetEdget(Node<T> n1, Node<T> n2)

            {

                int index1 = findNode(n1);

                int index2 = findNode(n2);

                Matrix[index1, index2] = 1;

                Matrix[index2, index1] = 1;

            }

            private int findNode(Node<T> n)

            {

                int index = -1;

                for (int i = 0; i < this.num; i++)

                {

                    var a = arryNode[i]; index++;

                    if (a.Equals(n))

                    {

                        return i;

                    }

                }

                return index;

            }

            public void PrintMatix()

            {

                for (int i = 0; i < this.num; i++)

                {

                    for (int j = 0; j < this.num; j++)

                    {

                        Console.Write("{0}  ", Matrix[i, j]);

                    }

                    Console.WriteLine();

                }

            }

            private Node<T> findNeighbor(Node<T> node)

            {

                int index1 = findNode(node);

                int index2 = -1;

                for (int i = 0; i < this.num; i++)

                {

                    if (Matrix[index1, i] == 1)

                    {

                        if (arryNode[i].accessed == false)

                        {

                            index2 = i;

                            break;

                        }

                    }

                }

                if (index2 == -1)

                {

                    return null;

                }

                return arryNode[index2];

            }

            /// <summary>

            /// 通过邻接节点来获取下一个节点

            /// </summary>

            /// <param name="node1"></param>

            /// <param name="node2"></param>

            /// <returns></returns>

            private Node<T> findNeighbor2(Node<T> node1, Node<T> node2)

            {

                int index1 = findNode(node1);

                int j = findNode(node2);

                int index2 = -1;

                for (int i = j; i < this.num; i++)

                {

                    if (Matrix[index1, i] == 1)

                    {

                        if (arryNode[i].accessed == false)

                        {

                            index2 = i;

                            break;

                        }

                    }

                }

                if (index2 == -1)

                {

                    return null;

                }

                return arryNode[index2];

            }

            public void DSF(Node<T> node)

            {

                if (node.accessed == true)

                {

                    return;

                }

                Console.Write("{0} ", node.t);

                node.accessed = true;

                var neighbor = findNeighbor(node);

                while (neighbor != null)

                {

                    DSF(neighbor);

                    neighbor = findNeighbor2(node, neighbor);

                }

            }

        }

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  • 原文地址:https://www.cnblogs.com/bruce1992/p/15138265.html
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