基本的dijkstra算法

基本的dijkstra算法是求单源点到其余各点的最短路径，下面的dijkstra可以返回两个顶点之间的最短路径。

返回数组里储存的是从起始顶点到结束顶点的最短路径经过的点的顺序。

package DijkstraJingxi;public class Dijkstra{public void dijkstra(int n, int v, int dist[], int prev[],int[][] c){ int maxint = Integer.MAX_VALUE; // 表示最大整数上限boolean[] s = new boolean[n]; //记录该点是否被访问过for(int i = 0; i < n; i++){dist[i] = c[v][i]; //目的地点初始化s[i] = false; //记录第i个点是否被访问过，初始化为false；if(dist[i] == maxint){prev[i] = 0;}else{prev[i] = v; //起始点}}dist[v] = 0;s[v] = true; //被访问过for(int i = 0; i < n+1; i++){int temp = maxint;int u = v;for(int j = 0; j < n; j++){if((!s[j]) && (dist[j] < temp)){u = j; //得到最短路径的终点temp = dist[j];}}s[u] = true;for(int j = 0; j < n; j++){if((!s[j]) && (c[u][j] < maxint)){int newdist = dist[u] + c[u][j];if (newdist < dist[j]){dist[j] = newdist; //新的最短路径prev[j] = u; //最短路径的上一个点}}}}}public int[] shortestPath(Graphm G, int v1, int v2){int n = G.n();int q = 0;int[] way = new int[n];int[] dist = new int[n];int[] prev = new int[n];int[][] c = new int[n][n];//路径初始化for(int i = 0; i < n; i++){for(int j = 0; j < n; j++){c[i][j] = G.Matrix[i][j][0];}}//调用dijkstra算法，得到最短路dijkstra(n, v1, dist, prev,c );//得到路径int w = v2;while(w != v1){q++;way[q] = prev[w];w = prev[w];}//得到正确顺序的路径int[] ret = new int[q + 1];int i, j;for(i = 0, j = q ; j >= 1; i++, j--){ ret[i] = way[j];}//路径的终点ret[i] = v2;return ret;}}package a;import java.util.*;//节点class Node{int name;Node fathernode;}//路径class Route{int a;int b;double length;public Route(int x,int y,double len){a=x;b=y;length=len;}}class Rsinfo{int name;double length;}//结果class Result{ArrayList<Rsinfo> rlist;double length;}//public class ShortCut {ArrayList<Node> nodelst;ArrayList<Integer> plist,vlist;double[][] la,lb,w;int[] seq;int N;int sN;int r=0;//nlist 表示节点的列表，public void init(ArrayList<Integer> nlist) {N = nlist.size();la=new double[N][ ];lb=new double[N][ ];w=new double[N][ ];seq=new int[N];plist=new ArrayList<Integer>();vlist=new ArrayList<Integer>();//----------------------------------for(int i=0;i<N;i++){la[i]=new double[N];lb[i]=new double[N];w[i]=new double[N];}//----------------------------------for(int i=0;i<N;i++){seq[i]=nlist.get(i);}//------------------------------------for(int i=0;i<N;i++){for(int j=0;j<N;j++){la[i][j]=1000000;lb[i][j]=1000000;w[i][j]=1000000;}}}public void addNode(ArrayList<Route> ndlist) {Route rt;int x,y;int len=ndlist.size();for(int i=0;i<len;i++){rt=ndlist.get(i);x=this.getChgNum(rt.a);y=this.getChgNum(rt.b);w[x][y]=rt.length;w[y][x]=rt.length;}}//获得经过转换后的数字public int getChgNum(int n){for(int i=0;i<N;i++){if(seq[i]==n)return i;}return 0;}//获得原来的数字public int getOrgNum(int n){return seq[n];}public void getShortCut(Result rs,int root) {int flag=0;flag=this.getChgNum(root);//初始化标号集合rs.rlist=new ArrayList<Rsinfo>();for(int i=0;i<N;i++){if(i==flag){flag=i;vlist.add(i);lb[0][flag]= 0;continue;}plist.add(i);}for(int i=0;i<N;i++){la[0][i] = w[flag][i] ;System.out.println("0 "+ i+" "+w[flag][i]);}r=1;//求出最短路径while(true){Rs2 r2=new Rs2();this.Minla(r2);this.show(la);this.show(plist);lb[r][r2.i]=r2.min;this.Remove(r2.i);this.add(rs, r2.i,r2.min);if(plist.size()==0)break;this.Minlb( r2.i);}}public void Remove(int n){for(int i=0;i<plist.size();i++){if(plist.get(i)==n){plist.remove(i);return;} }}public void add(Result rt,int n,double length) {vlist.add(n);Rsinfo rs=new Rsinfo();=this.getOrgNum(n);rs.length=length;rt.rlist.add(rs);}public void Minla(Rs2 rs){double min=10000000;int flag=0;for(int i=0;i<N;i++){if(this.InP(i)){if(la[r-1][i]<=min){min=la[r-1][i];flag=i;}}}rs.i=flag;rs.min=min;}public void Minlb(int n){double min=10000000;int flag=0;double sum=0;for(int i=0;i<N;i++){if(this.InP(i)){sum=lb[r][n]+w[n][i];if(la[r-1][i]<sum)min=la[r-1][i];else min=sum;la[r][i]=min;}}r++;}//查看是否在P集合中public boolean InP(int n){int len=plist.size();for(int i=0;i<len;i++){if(n==plist.get(i))return true;}return false;}public void show(double[][] t) {for(int i=0;i<N;i++){for(int j=0;j<N;j++){System.out.print(t[i][j]+" ");}System.out.println("");}System.out.println("****************************"); }public void show(ArrayList<Integer> list){System.out.println("###");for(int i=0;i<list.size();i++)System.out.print(" " +list.get(i));System.out.println("");}}//返回两个数字class Rs2{int i;double min;}。