C＃实现图的深度优先遍历--非递归代码

本文介绍C#实现图的深度优先遍历–非递归代码
1、程序如下所示
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace 图的应用__深度优先搜索算法
{
using VertexType = System.Char;//顶点数据类型别名声明
using EdgeType = System.Int16;//带权图中边上权值的数据类型别名声明
class Program
{
public const int MAxVertexNum = 100;//顶点数目的最大值
public const int MAXSize = 100;
static void Main(string[] args)
{
MGraph G = new MGraph();
int u;
int[] d = new int[MAxVertexNum];
G.vexnum = 8;
G.arcnum = 8;
G.vex = new VertexType[MAxVertexNum];
G.Edge = new EdgeType[MAxVertexNum, MAxVertexNum];
for (int i = 0; i < MAxVertexNum; ++i)
{
for (int j = 0; j < MAxVertexNum; ++j)
{
G.Edge[i, j] = 0;
}
}
//图的赋值
G.vex[0] = ‘a’; G.vex[1] = ‘b’; G.vex[2] = ‘c’; G.vex[3] = ‘d’; G.vex[4] = ‘e’; G.vex[5] = ‘f’;
G.vex[6] = ‘g’; G.vex[7] = ‘h’;
G.Edge[0, 1] = 1; G.Edge[0, 2] = 1;
G.Edge[1, 0] = 1; G.Edge[1, 3] = 1; G.Edge[1, 4] = 1;
G.Edge[2, 0] = 1; G.Edge[2, 5] = 1; G.Edge[2, 6] = 1;
G.Edge[3, 1] = 1;
G.Edge[4, 1] = 1; G.Edge[4, 7] = 1;
G.Edge[5, 2] = 1;
G.Edge[6, 2] = 1;
G.Edge[7, 4] = 1;
Console.WriteLine(“递归深度优先：”);
DFS_Traverse(G);
Console.ReadLine();
}

    /// <summary>
    /// 图的定义--邻接矩阵
    /// </summary>
    public struct MGraph
    {
        public VertexType[] vex;//顶点表数组
        public EdgeType[,] Edge;//临接矩阵、边表
        public int vexnum, arcnum;//图的当前顶点数和弧数
    }
    /// <summary>
    /// 图的定义--邻接表法
    /// </summary>
    public class ArcNode
    {//边表节点
        public int adjvex;
        public ArcNode next;
    }
    public class VNode
    {  //顶点表节点
        VertexType data;//顶点信息
        ArcNode first;//只想第一条依附改顶点的弧的指针
    }
    public class ALGraph
    {
        VNode[] vertices;   //邻接表
        int vexnum, arcnum;//图的顶点数和弧数
    }
    /// <summary>
    /// 深度优先搜索的递归实现
    /// </summary>
    /// <param name="G"></param>
    /// <param name="v"></param>
    /// <returns></returns>
    static void DFS_Traverse(MGraph G) {
        bool[] visited = new bool[MAxVertexNum];
        for (int i=0;i<G.vexnum;++i) {
            visited[i] = false;            }

        for (int v=0;v<G.vexnum;++v) {
            if (!visited[v]) {
                DFS2(G,v,ref visited);
            }

        }

    }
    /// <summary>
    /// 递归实现
    /// </summary>
    /// <param name="G"></param>
    /// <param name="v"></param>
    static void DFS(MGraph G,int v, ref bool[] visited) {
        visit(G,v);
        visited[v] = true;
        for (int w=FirstNeighbor(G,v); w>=0; w=NextNeighbor(G,v,w)) {
            if (!visited[w]) {
                DFS(G, w, ref visited);
            }
          
        }
    }
    /// <summary>
    /// 非递归实现
    /// </summary>
    /// <param name="G"></param>
    /// <param name="v"></param>
    static void DFS2(MGraph G, int v, ref bool[] visited) {
        SqStack S = new SqStack();
        S.data = new int[MAxVertexNum];
        Push(ref S,v);//入栈
        while (!StackEmpty(S)) {
            PoP(ref S, ref v);
            if (!visited[v]) { visit(G, v); }
            visited[v] = true;
            for (int w=FirstNeighbor(G,v);w>=0;w=NextNeighbor(G,v,w)) {
                if (!visited[w]) {
                    Push(ref S, w);
                }

            }
        }

    }
    //控制台打印遍历点
    static void visit(MGraph G, int v)
    {
        Console.Write(G.vex[v] + " ");
    }

    //查找G中，V顶点的首个邻接点
    static int FirstNeighbor(MGraph G, int v)
    {
        int b = -1;
        for (int i = 0; i < G.vexnum; ++i)
        {
            if (G.Edge[v, i] == 1)
            {
                b = i;
                break;
            };
        }
        return b;//返回首个邻接点
    }
    //查找G中，V顶点的W邻节点后的下一个邻接点
    static int NextNeighbor(MGraph G, int v, int w)
    {
        int b = -1;
        for (int i = w + 1; i < G.vexnum; ++i)
        {
            if (G.Edge[v, i] == 1)
            {
                b = i;
                break;
            };
        }
        return b;//返回下一个邻接点
    }

    /// <summary>
    /// 栈定义
    /// </summary>
    public struct SqStack
    {
        public int[] data;
        public int top;//栈顶

    }
    /// <summary>
    /// 判断栈是否为空
    /// </summary>
    /// <param name=""></param>
    /// <returns></returns>
   static bool StackEmpty(SqStack S)
    {
        if (S.top == -1)
        {
            return true;
        }
        else
        {
            return false;
        }
    }
    /// <summary>
    /// 栈初始化
    /// </summary>
    /// <param name="S"></param>
    static void InitStack(ref SqStack S)
    {
        S.top = -1;
    }
    /// <summary>
    /// 压栈
    /// </summary>
    /// <param name="S"></param>
    /// <returns></returns>
    static bool Push(ref SqStack S, int e)
    {
        if (S.top >= MAxVertexNum - 1)
        {
            return false;
        }
        S.top = S.top + 1;
        S.data[S.top] = e;//先加1，再进栈
        return true;
    }
    /// <summary>
    /// 出栈
    /// </summary>
    /// <param name="S"></param>
    /// <param name="e"></param>
    /// <returns></returns>
    static bool PoP(ref SqStack S, ref int e)
    {
        if (S.top == -1) { return false; }
        e = S.data[S.top--];//出栈
        return true;
    }
    /// <summary>
    /// 
    ///读取栈顶元素
    /// </summary>
    /// <param name="S"></param>
    /// <param name="e"></param>
    /// <returns></returns>
    bool GetTop(ref SqStack S, ref int e)
    {

        if (S.top == -1) { return false; }
        e = S.data[S.top];//读取元素
        return true;

    }



}

}

2、测试如下：