Dijkstra Algorithm 实现

using UnityEngine;using System;using System.Collections;using System.Collections.Generic;public class DijkstraAlgorithm : MonoBehaviour{public string StartPos = "a";public string TargetPos = "e";public bool CalculateAgain = false;// 顶点集private List<string> VertexSet = new List<string>(){"a", "b", "c", "d", "e"};// 路径值private Dictionary<string, int> valueMap = new Dictionary<string, int>();//已处理顶点private List<string> _AfterCalculate = new List<string>();//未处理顶点private List<string> _NotCalculte = new List<string>();// 顶点权值记录private Dictionary<string, int> vertexValue = new Dictionary<string, int>();// 第一个是目标节点，后面是路径private Dictionary<string, string> PathRecord = new Dictionary<string, string>();private void DijkstraAlgo(string startVertex, string targetVertex){// 清除掉所有信息vertexValue.Clear();PathRecord.Clear();_NotCalculte.Clear();_AfterCalculate.Clear();valueMap.Clear();// 初始化路径图数据InitPathValue();InitVertexValue();// 设置起点的路径值为0vertexValue[startVertex] =  0;PathRecord.Add(startVertex, startVertex);// 设置未处理的顶点列表为所有的顶点_NotCalculte.AddRange(VertexSet);while(_NotCalculte.Count > 0){// 找到权值最小的作为起点// 找到最小权值顶点string minVertex = _NotCalculte[0];int minVertexValue = vertexValue[minVertex];for(int index = 0, imax = _NotCalculte.Count; index < imax; index++){string crtVertex = _NotCalculte[index];int crtVertexValue = vertexValue[crtVertex];if(minVertexValue > crtVertexValue){minVertex = crtVertex;minVertexValue = crtVertexValue;}}string tempStart = minVertex;// 以起点开始，计算其它顶点的权值for(int index = 0, imax = _NotCalculte.Count; index < imax; index++){string targetPos = _NotCalculte[index];// 查看当前点到每个点的路径值int pathValue = GetPathValue(tempStart, targetPos);if(pathValue == int.MaxValue){continue;}// 在有路径的情况下，比较当前的顶点权值// 当前点的路径权值直接从记录中查找，新的权值等于开始点的权值+ 路径权值int crtValue = vertexValue[targetPos];int preVextex = vertexValue[tempStart];if(crtValue > preVextex + pathValue){vertexValue[targetPos] = preVextex + pathValue;// 记录其路径if(PathRecord.ContainsKey(targetPos)){PathRecord.Remove(targetPos);}// 路径等于前一节点 + 当前节点string crtPath = PathRecord[tempStart] + targetPos;PathRecord.Add(targetPos, crtPath);}}// 将最小权值点移动到已处理顶点列表中_AfterCalculate.Add(tempStart);_NotCalculte.Remove(tempStart);}PrintMinPathRecord(targetVertex);}void Update(){if(CalculateAgain){CalculateAgain = false;DijkstraAlgo(StartPos, TargetPos);}}private void InitPathValue(){valueMap.Add("ab", 3);valueMap.Add("ac", 2);valueMap.Add("bc", 2);valueMap.Add("cd", 1);valueMap.Add("ce", 6);valueMap.Add("de", 1);}private void InitVertexValue(){for(int index = 0, imax = VertexSet.Count; index < imax; index++){string vertex = VertexSet[index];vertexValue.Add(vertex, int.MaxValue);}}private void PrintVertexValue(){foreach(var key in vertexValue.Keys){Debug.Log(key + " = " + vertexValue[key]);}}private void PrintMinPathRecord(string targetPos){string minPath;if(PathRecord.TryGetValue(targetPos, out minPath)){Debug.Log("PATH = " + minPath);}}private void PrintMinPathRecord(){Debug.Log("************Min PATH *****************");foreach(var key in PathRecord.Keys){Debug.Log(key + " = " + PathRecord[key]);}Debug.Log("************End PATH *****************");}private string GetVertexMinPath(string vertex){string minPath;if(!PathRecord.TryGetValue(vertex,out minPath)){return null;}return minPath;}private int GetPathValue(string s, string d){foreach(var key in valueMap.Keys){string tempS = key.Substring(0, 1);string tempD = key.Substring(1, 1);if(tempS == s && tempD == d){return valueMap[key];}}return int.MaxValue;}}