// 實驗小結 吳新強於2013年3月19日19:20:45 桂電 2507實驗室
// 主要學習圖結構的實現輸出以Dijkstra 算法的最小路徑的實現
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Chapter16_1
{
class chapter16
{
static void Main()
{
Graph theGraph = new Graph();
theGraph.AddVertex("A");
theGraph.AddVertex("B");
theGraph.AddVertex("C");
theGraph.AddVertex("D");
theGraph.AddVertex("E");
theGraph.AddVertex("F");
theGraph.AddVertex("G");
theGraph.AddEdge(0, 1, 2);
theGraph.AddEdge(0, 3, 1);
theGraph.AddEdge(1, 3, 3);
theGraph.AddEdge(1, 4, 10);
theGraph.AddEdge(2, 5, 5);
theGraph.AddEdge(2, 0, 4);
theGraph.AddEdge(3, 2, 2);
theGraph.AddEdge(3, 5, 8);
theGraph.AddEdge(3, 4, 2);
theGraph.AddEdge(3, 6, 4);
theGraph.AddEdge(4, 6, 6);
theGraph.AddEdge(6, 5, 1);
Console.WriteLine();
Console.WriteLine("Shortest paths:");
Console.WriteLine();
theGraph.Path();
Console.WriteLine();
}
}
public class DistOriginal
{
public int distance;
public int parentVert;
public DistOriginal(int pv, int d)
{
distance = d;
parentVert = pv;
}
}
public class Vertex
{
public string label;
public bool isInTree;
public Vertex(string lab)
{
label = lab;
isInTree = false;
}
}
public class Graph
{
private const int max_verts = 20;
int infinity = 1000000;
Vertex[] vertexList;
int[,] adjMat;
int nVerts;
int nTree;
DistOriginal[] sPath;
int currentVert;
int startToCurrent;
public Graph()
{
vertexList = new Vertex[max_verts];
adjMat = new int[max_verts, max_verts];
nVerts = 0;
nTree = 0;
for (int j = 0; j <= max_verts - 1; j++)
for (int k = 0; k <= max_verts - 1; k++)
adjMat[j, k] = infinity;
sPath = new DistOriginal[max_verts];
}
public void AddVertex(string lab)
{
vertexList[nVerts] = new Vertex(lab);
nVerts++;
}
public void AddEdge(int start, int theEnd, int weight)
{
adjMat[start, theEnd] = weight;
}
public void Path()
{
int startTree = 0;
vertexList[startTree].isInTree = true;
nTree = 1;
for (int j = 0; j <= nVerts; j++)
{
int tempDist = adjMat[startTree, j];
sPath[j] = new DistOriginal(startTree, tempDist);
}
while (nTree < nVerts)
{
int indexMin = GetMin();
int minDist = sPath[indexMin].distance;
currentVert = indexMin;
startToCurrent = sPath[indexMin].distance;
vertexList[currentVert].isInTree = true;
nTree++;
AdjustShortPath();
}
DisplayPaths();
nTree = 0;
for (int j = 0; j <= nVerts - 1; j++)
vertexList[j].isInTree = false;
}
public int GetMin()
{
int minDist = infinity;
int indexMin = 0;
for (int j = 1; j <= nVerts - 1; j++)
if (!(vertexList[j].isInTree) && sPath[j].distance < minDist)
{
minDist = sPath[j].distance;
indexMin = j;
}
return indexMin;
}
public void AdjustShortPath()
{
int column = 1;
while (column < nVerts)
if (vertexList[column].isInTree)
column++;
else
{
int currentToFring = adjMat[currentVert, column];
int startToFringe = startToCurrent + currentToFring;
int sPathDist = sPath[column].distance;
if (startToFringe < sPathDist)
{
sPath[column].parentVert = currentVert;
sPath[column].distance = startToFringe;
}
column++;
}
}
public void DisplayPaths()
{
for (int j = 0; j <= nVerts - 1; j++)
{
Console.Write(vertexList[j].label + "=");
if (sPath[j].distance == infinity)
Console.Write("inf");
else
Console.Write(sPath[j].distance);
string parent = vertexList[sPath[j].parentVert].
label;
Console.Write("(" + parent + ") ");
}
}
}
}
實驗截圖：
