Dijkstra 最短路径算法C#实现

2019年3月17日 273次阅读来源: Dijkstra算法

算法不用细说，学过数据结构的同仁们都知道，前两天用到，用C#写出来了。

using System;
using System.Collections.Generic;
using System.Text;

namespace ShortedPath
{
    class Program
    {
        static int length=6;
        static string[] shortedPath=new string[length];
        static int noPath=2000;
        static int MaxSize = 1000;
        static int [,] G={{noPath,noPath,10,noPath,30,100},{noPath,noPath,5,noPath,noPath,noPath},{noPath,noPath,noPath,50,noPath,noPath},{noPath,noPath,noPath,noPath,noPath,10},{noPath,noPath,noPath,20,noPath,60},{noPath,noPath,noPath,noPath,noPath,noPath}};
        static string[] PathResult = new string[length];

        static int[] path1 = new int[length];
        static int[,] path2 = new int[length, length];
        static int[] distance2 = new int[length];

static void Main(string[] args)
{

            int dist1= getShortedPath(G,0,5,path1);
            Console.WriteLine(“点0到点5路径:”);
            for (int i=0; i < path1.Length; i++)
                Console.Write(path1[i].ToString()+” “);
            Console.WriteLine(“长度:” + dist1);

            int [] pathdist = getShortedPath(G, 0, path2);
            Console.WriteLine(“点0到任意点的路径:”);
            for (int j = 0; j < pathdist.Length; j++)
            {
                Console.WriteLine(“点0到” + j + “的路径:”);
                for (int i = 0; i < length; i++)
                    Console.Write(path2[j, i].ToString() + ” “);
                Console.WriteLine(“长度:” + pathdist[j]);
            }
            Console.ReadKey();
        }

        //从某一源点出发，找到到某一结点的最短路径
        static int getShortedPath(int[,]G, int start, int end,int [] path)
        {
            bool[] s = new bool[length]; //表示找到起始结点与当前结点间的最短路径
            int min; //最小距离临时变量
            int curNode=0; //临时结点，记录当前正计算结点
            int[] dist = new int[length];
            int[] prev = new int[length];

            //初始结点信息
            for (int v = 0; v < length; v++)
            {
                s[v] = false;
                dist[v] = G[start, v];
                if (dist[v] > MaxSize)
                    prev[v] = 0;
                else
                    prev[v] = start;
            }
            path[0] = end;
            dist[start] = 0;
            s[start] = true;
            //主循环
            for (int i = 1; i < length; i++)
            {
                min = MaxSize;
                for (int w = 0; w < length; w++)
                {
                    if (!s[w] && dist[w] < min)
                    {
                        curNode = w;
                        min = dist[w];
                    }
                }

s[curNode] = true;

                for (int j = 0; j < length; j++)
                    if (!s[j] && min + G[curNode, j] < dist[j])
                    {
                        dist[j] = min + G[curNode, j];
                        prev[j] = curNode;
                    }

            }
            //输出路径结点
            int e = end, step = 0;
            while (e != start)
            {
                step++;
                path[step] = prev[e];
                e = prev[e];
            }
            for (int i = step; i > step/2; i–)
            {
                int temp = path[step – i];
                path[step – i] = path[i];
                path[i] = temp;
            }
            return dist[end];
        }

        //从某一源点出发，找到到所有结点的最短路径
        static int[] getShortedPath(int[,] G, int start, int[,] path)
        {
            int[] PathID = new int[length];//路径（用编号表示）
            bool[] s = new bool[length]; //表示找到起始结点与当前结点间的最短路径
            int min; //最小距离临时变量
            int curNode = 0; //临时结点，记录当前正计算结点
            int[] dist = new int[length];
            int[] prev = new int[length];
            //初始结点信息

            for (int v = 0; v < length; v++)
            {
                s[v] = false;
                dist[v] = G[start, v];
                if (dist[v] > MaxSize)
                    prev[v] = 0;
                else
                    prev[v] = start;
                path[v,0] = v;
            }

            dist[start] = 0;
            s[start] = true;
            //主循环
            for (int i = 1; i < length; i++)
            {
                min = MaxSize;
                for (int w = 0; w < length; w++)
                {
                    if (!s[w] && dist[w] < min)
                    {
                        curNode = w;
                        min = dist[w];
                    }
                }

s[curNode] = true;

            }
            //输出路径结点
            for (int k = 0; k < length; k++)
            {
                int e = k, step = 0;
                while (e != start)
                {
                    step++;
                    path[k,step] = prev[e];
                    e = prev[e];
                }
                for (int i = step; i > step / 2; i–)
                {
                    int temp = path[k,step – i];
                    path[k,step – i] = path[k,i];
                    path[k,i] = temp;
                }
            }
            return dist;

}
}
}

    原文作者：Dijkstra算法
    原文地址: https://blog.csdn.net/chaihuo/article/details/1853624
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