Classic Graph algorithm Java code Practice: Bfs,dfs and several shortest path algorithms

public class City {string name, int id;static int idcounter = 0;public City (string name) {this.name=name;id = idcounter++; }}

Import Java.util.arraylist;public class Graph {public static void main (string[] args) {//TODO auto-generated method STUBMA P M = new Map (12); City A = new City ("a"); City B = New City ("B"); City C = new City ("C"); City d = new City ("D"); City e = new City ("E"); City F = new City ("F"); City g = new City ("G"); City h = new City ("H"); City i = new City ("I"); City j = New City ("J"); City k = new City ("K"); City L = new City ("L"); M.createedge (a,b,3); M.createedge (a,c,5); M.createedge (a,d,4); M.createedge (b,f,6); M.createedge (c,d,2); M.createedge (c,g,4); M.createedge (d,e,1); M.createedge (d,h,5); M.createedge (e,f,2); M.createedge (e,i,4); M.createedge (f,j,5); M.createedge (g,h,3); M.createedge (g,k,6); M.createedge (h,i,6); M.createedge (h,k,7); M.createedge (i,j,3); M.createedge (i,l,5); M.createedge (j,l,9); M.createedge (k,l,8); System.out.println ("The graph is:\n"); System.out.println (M); System.out.println (); System.out.println ("findpathbydfs:a to K"); M.findpathbydfs (A,K); System.out.println (); System.out.println ("Findpathbybfs:a to K "); M.FINDPATHBYBFS (A,K); System.out.println (); System.out.println ("Bellmanford from A:"); M.bellmanford (a); System.out.println (); System.out.println ("Dijkstra from A:"); M.dijkstra (a); System.out.println (); System.out.println ("bellmanford,print example from A:"); M.floydwarshall (); M.printfloydwarshallforonecity (a);}}

Import Java.util.arraylist;import Java.util.linkedlist;import Java.util.queue;public class Map {double[][] A;public     Map (int n) {A = new double[n][n]; for (int i = 0;i < a.length;i++) {for (int j = 0;j < a.length;j++) {if (i = = j) a[i           ][J] = 0;           else A[i][j] =-1;        }}}arraylist<city> cities = new arraylist<city> ();p rivate double[] d;private void Relax (int u,int v) { if (D[v]>d[u]+a[v][u]) d[v]=d[u]+a[v][u];}     Private double[][] dd = null;public void Floydwarshall () {DD = new double[a.length][a.length];     int i,j,k;                 for (i = 0;i < a.length;i++) {for (j = 0;j < a.length;j++) {if (a[i][j]>0)           DD[I][J] = A[i][j];           else if (i = = j) Dd[i][j] = 0;           else dd[i][j] = 99999999;      }} for (k = 0;k < a.length;k++) for (i = 0;i < a.length;i++) for (j = 0;j < a.length;j++) { if (Dd[i][j] > DDI       [K] + dd[k][j]) {dd[i][j] = Dd[i][k] + dd[k][j]; }}}public void Printfloydwarshallforonecity (city city) {System.out.println ("Floydwarshall:"); if (DD = = null) { Floydwarshall ();} for (int i=0;i<a.length;i++) {System.out.printf ("from%s to%s shortest path is:%f\n", City.name,cities.get (i). Name, Dd[city.id][i]);}} public void Dijkstra (city city) {Dijkstra (city.id); System.out.println ("Dijkstra:"); for (int. i=0;i<a.length;i++) {System.out.printf ("from%s to%s shortest path is:%f\n ", City.name,cities.get (i). Name,d[i]);}}        public void Dijkstra (int srcid) {D = new double[a.length];            for (int i=0;i<a.length;i++) {d[i]=999999999;        } d[srcid]=0;        int[] q = new Int[a.length]; int ql=0,qf=0;        Queue for (int i=0;i<a.length;i++) q[ql++]=i;               while (QF!=QL) {int min=qf;         for (int i=qf;i<ql;i++) {if (D[q[i]]<d[q[min]]) {      Min=i;               }} int id = Q[QF];               Q[QF] = Q[min]; Q[min] = ID;               Q[QF] is the min int u=q[qf++]; for (int i=0;i<a.length;i++) {if (a[u][i]>0) {RelA                  X (U,i); }}}}public void Bellmanford (city city) {Bellmanford (city.id); System.out.println ("Bellmanford:"); for (int. i=0;i<a.length;i++) {System.out.printf ("from%s to%s shortest path is:% F\n ", City.name,cities.get (i). Name,d[i]);}} public void Bellmanford (int srcid) {D = new double[a.length];for (int i=0;i<a.length;i++) {D[i] = 99999999;//Infinity}d[ SRCID] = 0;for (int i=0;i<a.length;i++)//Outer loop number {for (int. j=0;j<a.length;j++) {for (int k=0;k<a.length;k++) {if ( a[j][k]>0) {relax (j,k);}}}} queue<integer> bfsqueue = new linkedlist<integer> () boolean[] bfsflag;int bsfpre[];p ublic void FINDPATHBYBFS (city src,city DST) {System.out.printf ("BFs Find path between '%s ' and '%s '!\n", Src.name,dst.name) Findpathbybfs (src.id, dst.id);p Rintbfs (dst.id) ;} public void Findpathbybfs (int srcid,int dstid) {bsfpre = new int[a.length];bfsqueue.clear (); bfsflag = new boolean[ a.length];for (int i=0;i<a.length;i++) {Bfsflag[i] = false;bsfpre[i] =-1;} Bfsqueue.offer (SRCID); Bfsflag[srcid] = True;while (!bfsqueue.isempty ()) {int current = Bfsqueue.poll (); for (int index=0 index<a.length;index++) {if (current = = index) continue;if (a[current][index]>0)//both are connected {if (index = = Dstid)// The target is found {Bfsflag[index] = True;bsfpre[index] = current;return;//directly returns}IF (Bfsflag[index] = = false)//Suppose not interviewed {Bfsflag[index] = True;bsfpre[index] = current;bfsqueue.offer (index);}}}} private void Printbfs (int dstid) {int index = dstid;do{system.out.printf ("<-%s", Cities.get (Index). name); index = Bsfpre[index];} while (Index! =-1); System.out.println ();} arraylist<integer> Dfspath = new arraylist<integer> (); boolean[] dfsflag;private void PrintDFS () {for (IntegEr node:dfspath) {System.out.printf ("->%s", Cities.get (node). name);} System.out.println ();} public void Findpathbydfs (city src,city DST) {System.out.printf ("Dfs find path between '%s ' and '%s '!\n", Src.name, Dst.name); Findpathbydfs (Src.id, dst.id);} public void Findpathbydfs (int srcid,int dstid) {dfspath.clear ();d fsflag = new Boolean[a.length];for (int i=0;i< a.length;i++) {Dfsflag[i] = false;} Dfspath.add (SRCID);d fsflag[srcid] = True;dfs (srcid, Dstid);p Rintdfs ();} private void Dfs (int srcid,int dstid) {for (int index=0;index<a[srcid].length;index++) {if (srcid = = index) continue;if (a[srcid][index]>0)//both connect {if (index = = dstid)//Find target {Dfsflag[index] = True;dfspath.add (index); return;} if (dfsflag[index] = = false)//Assume that the node has not interviewed {Dfsflag[index] = True;dfspath.add (index);d FS (Index,dstid); if (Dfsflag[dstid] = = false)//target not found Dfspath.remove (index); else return;}}} public void Createedge (city A, City B, double W) {a[a.id][b.id]=w; A[b.id][a.id]=w;//added by Me!cities.add (a.id,a); Cities.add (b.id,b);} Public STRing toString () {String r = "I am a map of" + A.length + "cities."; R + = "My connections are:\n"; for (int. i=0;i<a.length;i++) {for (int j=0;j<a[0].length;j++) r+=a[i][j]+ "\ T"; r+= "\ n" ;} return r;}}

Classic Graph algorithm Java code Practice: Bfs,dfs and several shortest path algorithms