求C#的最短路径算法（Dijkstra）

[lmn788209]

哪个朋友有啊 谢谢了

[会飞的老鱼]

顶

[Snowdust]

网上搜的：

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

namespace Greedy
{   
    class Marx
    {
        private int[] distance;        
        private int row;
        private ArrayList ways = new ArrayList();

        public Marx(int n,params int[] d)
        {
            this.row = n;
            distance = new int[row * row];
            for (int i = 0; i < row * row; i++)
            {
                this.distance[i] = d[i];              
            }
            for (int i = 0; i < this.row; i++)  //有row个点，则从中心到各点的路有row-1条
            {
                ArrayList w = new ArrayList();
                int j = 0;
                w.Add(j);
                ways.Add(w);
            }
        }
        //------------------------------
        public void Find_way()
        {
            ArrayList S = new ArrayList(1);
            ArrayList Sr = new ArrayList(1);
            int []Indexof_distance=new int[this.row];
            
            for(int i=0; i < row; i++)
            { 
                Indexof_distance[i]=i;
            }

            S.Add( Indexof_distance[0] );        

            for (int i = 0; i < this.row; i++)
            {
                Sr.Add( Indexof_distance[i] );
            }
            Sr.RemoveAt(0);
            int[] D = new int[this.row];    //存放中心点到每个点的距离
           
         //---------------以上已经初始化了，S和Sr(里边放的都是点的编号)------------------
            int Count = this.row - 1;
            while (Count>0)
            {
                //假定中心点的编号是0的贪吃法求路径
                for (int i = 0; i < row; i++)
                    D[i] = this.distance[i];

                int min_num = (int)Sr[0];  //距中心点的最小距离点编号

                foreach (int s in Sr)
                {
                    if (D[s] < D[min_num]) min_num = s;
                }
        
                //以上可以排序优化
                S.Add(min_num);
                Sr.Remove(min_num);
                //-----------把最新包含进来的点也加到路径中-------------
                ((ArrayList)ways[min_num]).Add(min_num);
                //-----------------------------------------------
                foreach (int element in Sr)
                {
                    int position = element * (this.row) + min_num;
                    bool exchange = false;      //有交换标志

                    if (D[element] < D[min_num] + this.distance[position])
                        D[element] = D[element];
                    else
                    {
                        D[element] = this.distance[position] + D[min_num];
                        exchange = true;
                    }
                    //修改距离矩阵                   
                    this.distance[element] = D[element];
                    position = element * this.row;      
                    this.distance[position] = D[element];

                    //修改路径---------------
                    if (exchange == true)
                    {                       
                        ((ArrayList)ways[element]).Clear();
                        foreach (int point in (ArrayList)ways[min_num])
                            ((ArrayList)ways[element]).Add(point);
                    }
                }
                --Count;
           }
        }
        //----------------------------------------------------
        public void Display()
        {         
            //------中心到各点的最短路径----------
            Console.WriteLine("中心到各点的最短路径如下: \n\n");
            int sum_d_index = 0;
            foreach(ArrayList mother in ways)
            {
                foreach (int child in mother)
                    Console.Write("V{0} -- ", child+1);
                Console.WriteLine("    路径长 {0}",distance[sum_d_index++]);
            }
        }
    }

    class MainEnterPoint
    {   
        static void Main(string[] args)
        {
            int r;     //列数
            Console.Write("请输入点个数（含配送中心点）: ");
            Int32.TryParse(Console.ReadLine(), out r);
            Console.WriteLine("各点分别为: \n");
            for (int i = 0; i < r; i++)
                Console.Write("V{0} ", i);
            Console.Write("  假定第一个点是配送中心");
            Console.WriteLine("\n\n输入各点之间的距离(无通径的用个大整数表示)\n");

            int[] a = new int[r * r];            
            int da;

            for (int i = 0; i < r; i++)
            {
                for (int j = i + 1; j < r; j++)
                {
                    Console.Write("V{0} 到 V{1}的距离是:  ",i,j);
                    Int32.TryParse(Console.ReadLine(), out da);
                    a[i * r + j] = da;
                    Console.WriteLine();
                }
            }
            //----完善距离矩阵(距离矩阵其实可以是个上三角矩阵，
            //----但为了处理方便，还是将其完整成一个对称阵)-----------
            for (int i = 0; i < r; i++)
            {
                for (int j = 0; j < r; j++)
                {
                    if (i == j)
                    {
                        a[i * r + j] = 0;
                    }
                    a[j * r + i] = a[i * r + j];
                }
            }      
            Marx m=new Marx(r,a);
            Console.WriteLine();
            m.Find_way();
            m.Display();
        }
    }
}

//该程序不但能够算出从中心到各点的最短路径距离,而且把路径也保存了下来.

[wuyq11]

参考

[mayonglong]

[Quote=引用 2 楼 snowdust 的回复:]
网上搜的：
C# codeusing System;using System.Collections;using System.Text;namespace Greedy
{class Marx
{privateint[] distance;privateint row;private ArrayList ways=new ArrayList();public Marx(int n,paramsint[] d)
{this.row= n;
distance=newint[row* row];for (int i=0; i< row* row; i++)
{this.distance[i]= d[i];
}for (int i=0; i<this.row; i++)//有row个点，则从中心到各点的路有row-1条 {
ArrayList w=new ArrayList();int j=0;
w.Add(j);
ways.Add(w);
}
}//------------------------------publicvoid Find_way()
{
ArrayList S=new ArrayList(1);
ArrayList Sr=new ArrayList(1);int []Indexof_distance=newint[this.row];for(int i=0; i< row; i++)
{
Indexof_distance[i]=i;
}

S.Add( Indexof_distance[0] );for (int i=0; i<this.row; i++)
{
Sr.Add( Indexof_distance[i] );
}
Sr.RemoveAt(0);int[] D=newint[this.row];//存放中心点到每个点的距离//---------------以上已经初始化了，S和Sr(里边放的都是点的编号)------------------int Count=this.row-1;while (Count>0)
{//假定中心点的编号是0的贪吃法求路径for (int i=0; i< row; i++)
D[i]=this.distance[i];int min_num= (int)Sr[0];//距中心点的最小距离点编号foreach (int sin Sr)
{if (D[s]< D[min_num]) min_num= s;
}//以上可以排序优化 S.Add(min_num);
Sr.Remove(min_num);//-----------把最新包含进来的点也加到路径中------------- ((ArrayList)ways[min_num]).Add(min_num);//-----------------------------------------------foreach (int elementin Sr)
{int position= element* (this.row)+ min_num;bool exchange=false;//有交换标志if (D[element]< D[min_num]+this.distance[position])
D[element]= D[element];else
{
D[element]=this.distance[position]+ D[min_num];
exchange=true;
}//修改距离矩阵this.distance[element]= D[element];
position= element*this.row;this.distance[position]= D[element];//修改路径---------------if (exchange==true)
{
((ArrayList)ways[element]).Clear();foreach (int pointin (ArrayList)ways[min_num])
((ArrayList)ways[element]).Add(point);
}
}--Count;
}
}//----------------------------------------------------publicvoid Display()
{//------中心到各点的最短路径---------- Console.WriteLine("中心到各点的最短路径如下: \n\n");int sum_d_index=0;foreach(ArrayList motherin ways)
{foreach (int childin mother)
Console.Write("V{0} --", child+1);
Console.WriteLine(" 路径长 {0}",distance[sum_d_index++]);
}
}
}class MainEnterPoint
{staticvoid Main(string[] args)
{int r;//列数 Console.Write("请输入点个数（含配送中心点）:");
Int32.TryParse(Console.ReadLine(),out r);
Console.WriteLine("各点分别为: \n");for (int i=0; i< r; i++)
Console.Write("V{0}", i);
Console.Write(" 假定第一个点是配送中心");
Console.WriteLine("\n\n输入各点之间的距离(无通径的用个大整数表示)\n");int[] a=newint[r* r];int da;for (int i=0; i< r; i++)
{for (int j= i+1; j< r; j++)
{
Console.Write("V{0} 到 V{1}的距离是:",i,j);
Int32.TryParse(Console.ReadLine(),out da);
a[i* r+ j]= da;
Console.WriteLine();
}
}//----完善距离矩阵(距离矩阵其实可以是个上三角矩阵，//----但为了处理方便，还是将其完整成一个对称阵)-----------for (int i=0; i< r; i++)
{for (int j=0; j< r; j++)
{if (i== j)
{
a[i* r+ j]=0;
}
a[j* r+ i]= a[i* r+ j];
}
}
Marx m=new Marx(r,a);
Console.WriteLine();
m.Find_way();
m.Display();
}
}
}//该程序不但能够算出从中心到各点的最短路径距离,而且把路径也保存了下来.
[/Quote]

哥们用心了啊

[绿色夹克衫]

以前写过一个邻接矩阵实现的，效率一般，忙过这段时间，准备写一个邻接表配合斐波那契堆的。

[lmn788209]

谢谢各位啊

[noway8881]

class Dijkstra
    {        
        private int rank = 0;
        private int[,] L;
        private int[] C; 
        public int[] D;
        private int trank = 0;
        public Dijkstra(int paramRank,int [,]paramArray)
        {
            L = new int[paramRank, paramRank];
            C = new int[paramRank];
            D = new int[paramRank];
            rank = paramRank;
            for (int i = 0; i < rank; i++)
            {
                for (int j = 0; j < rank; j++) {
                    L[i, j] = paramArray[i, j];
                }
            }

            for (int i = 0; i < rank; i++)
            {
                C[i] = i;
            }
            C[0] = -1;          
            for (int i = 1; i < rank; i++)
                D[i] = L[0, i];
        }
        public void DijkstraSolving()
        {            
            int minValue = Int32.MaxValue;
            int minNode = 0;
            for (int i = 0; i < rank; i++)
            {
                if (C[i] == -1)
                    continue;
                if (D[i] > 0 && D[i] < minValue)
                {
                    minValue = D[i];
                    minNode = i;
                }
            }
            C[minNode] = -1;
            for (int i = 0; i < rank; i++)
            { 
                if (L[minNode, i] < 0)
                    continue;
                if (D[i] < 0) {
                    D[i] = minValue + L[minNode, i];
                    continue;
                }
                if ((D[minNode] + L[minNode, i]) < D[i])
                    D[i] = minValue+ L[minNode, i];
            }
        }
        public void Run()
        {
            for (trank = 1; trank >rank; trank++)
            {
                DijkstraSolving();
                Console.WriteLine("iteration" + trank);
                for (int i = 0; i < rank; i++)
                    Console.Write(D[i] + " ");
                Console.WriteLine("");
                for (int i = 0; i < rank; i++)
                    Console.Write(C[i] + " ");
                Console.WriteLine("");                
            }
        }
 }

[jianshao810]

只有到网上找啦。。顶下。