Question

Using java can someone help me create a program using the following instructions.

4. (70 points) Implement Dijkstra's algorithm for computing a shortest path from a designated vertex (A) to a designated vertex (B) in a directed graph. Your implementation should use a minimum heap as a supporting data structure. Please follow the instructions below.

Input file:

10
A J 18
A H 79
A I 81
J G 24
J F 76
G F 2
G H 50
F E 4
E D 2
D H 20
H C 50
I D 6
I C 97
I J 27
C B 22

Solution File:

142
A J G F E D H C B

Answer 1

CODE TO COPY:

import java.io.File;

import java.io.FileNotFoundException;

import java.io.PrintWriter;

import java.util.ArrayList;

import java.util.Comparator;

import java.util.HashMap;

import java.util.HashSet;

import java.util.Scanner;

import java.util.List;

import java.util.PriorityQueue;

//edge class to hold the edge source, destinationa and the weight of the edge

class GraphEdge{

private char from;

private char to;

private int weight;

public GraphEdge(char from, char to, int weight)

{

this.from=from;

this.to=to;

this.weight=weight;

}

public char getFrom()

{

return from;

}

public char getTo()

{

return to;

}

public int getWeight()

{

return weight;

}

public String toString()

{

return "From: "+from+"\tTo: "+to+"\tWeight: "+weight;

}

}

public class DijkstraAlgorithmTest {

public static void main(String[] args) throws FileNotFoundException {

File file=new File("dijkstraFile.txt");//input file

Scanner obj=new Scanner(file);//scanner object to read data from file

char source='A';//source vertex

char destination='B';//destination vertex

ArrayList<GraphEdge> edges=new ArrayList<GraphEdge>();//list to hold all edges

HashSet<Character> uniqueVertices=new HashSet<Character>();//all unique vertices in map

ArrayList<Character> allVertices=new ArrayList<Character>();//list to hold all vertices

int numberOfVertices=Integer.parseInt(obj.nextLine());

while(obj.hasNextLine())

{//while input file has lines left

String line=obj.nextLine();

String vertex[]=line.split(" ");//split the line into source vertex, destination vertex and the weight

GraphEdge edge=new GraphEdge(vertex[0].charAt(0), vertex[1].charAt(0), Integer.parseInt(vertex[2]));//create a new graphedge object from line data

edges.add(edge);

if(!uniqueVertices.contains(vertex[0].charAt(0)))

{//if vertex not present in unique vertices map, add it in map and arraylist

uniqueVertices.add(vertex[0].charAt(0));

allVertices.add(vertex[0].charAt(0));

}

if(!uniqueVertices.contains(vertex[1].charAt(0)))

{//if vertex not present in unique vertices map, add it in map and arraylist

uniqueVertices.add(vertex[1].charAt(0));

allVertices.add(vertex[1].charAt(0));

}

}

HashMap<Character, Integer> distance=new HashMap<Character, Integer>();

for(Character ch: allVertices)

{

distance.put(ch, Integer.MAX_VALUE);//add all vertices to distance map with initial distance as infinite i.e Integer.MAX_VALUE

}

distance.put(source, 0);//source distance is 0, update in distance map

//comparator to arrange the vertices in the priority queue in min heap fashion

Comparator<Character> cmp=new Comparator<Character>()

{

public int compare(Character a, Character b)

{

if(distance.get(a)<distance.get(b))

return -1;

else if(distance.get(a)==distance.get(b))

return 0;

else

return 1;

}

};

//create a priority queue

PriorityQueue<Character> pq=new PriorityQueue<Character>(cmp);//priority queue / min heap to arrange vertices in min heap fashion

for(Character ch: allVertices)

pq.add(ch);//add all the vertices to pq

String path="";//hold the final path from a to b

while(!pq.isEmpty())

{//while there are elements in the pq

char ch=pq.remove();//get the vertex

path+=ch;//append the vertex to path

if(ch==destination)//if reached destination

break;//loop out

List<GraphEdge> outVertex=getAllOutgoingEdges(edges, ch);

for(GraphEdge edge:outVertex)

{//for each egde in the outVertex list

if(pq.contains(edge.getTo()))

{//if the destination vertex in the edge is present in the pq

if(distance.get(ch)+edge.getWeight()<distance.get(edge.getTo()))

{//if new distance is less than the old distance

distance.put(edge.getTo(), distance.get(ch)+edge.getWeight());//put new distance

}

//the below 2 lines are executed to update the priority queue after change to distance

pq.remove(edge.getTo());//remove destination vertex of edge to pq

pq.add(edge.getTo());//add destination vertex of edge to pq

}

}

}

// solution file

File output=new File("DijkstraSolution.txt");

PrintWriter pw=new PrintWriter(output);

pw.println(distance.get(destination));//print the minuimum distance to destination to file

pw.println(path);//print the path to file

//print a successful message to the console

System.out.println("Successful!");

pw.flush();//flush the output to file

pw.close();//close pw

obj.close();//close obj

}

//get all the outgoing edges in a list from the source vetrtex

public static List<GraphEdge> getAllOutgoingEdges(ArrayList<GraphEdge> list, char source)

{

List<GraphEdge> result=new ArrayList<GraphEdge>();

for(GraphEdge edge: list)

{

if(edge.getFrom()==source)

result.add(edge);

}

return result;

}

}

PROGRAM SCREENSHOTS:

my java_programs - Chegg QA/c/May_2018/DijkstraAlgorithm Test.java - Eclipse File Edit Source Refactor Navigate Search Project Run Window Help Quick Access|: l i E ! 製な е 曰Console DUltimateFri.. D TreeTest java DListNodejava DApplicantTe ByReferenceE" J SegregateNe.. D Graph EdgeTe A DijkstraAlg ,s 9- 1 package May_2818; import java.io.File; 4 import java.io.FileNotFoundException; 5 import java.io.Printriter; 6 import java.util.ArrayList; 7 import java.util.Comparator; 8 import java.util.HashMap; 9 import java.uti1.HashSet; 10 import java.util.Scanner; 11 import java.util.List; 12 import java.util.PriorityQueue; 13 14 //edge class to hold the edge source, destinatiena and the weight of the edge 15 class GraphEdget 16 17 18 19 private char from; private char to; private int weight; 21 public GraphEdge(char from, char to, int weight) 23 24 25 26 27 28 public char getFrom() 29 this.from-from; this.to-to; this.weight-weight; return from; 32 33 public char getTo() 34 35 36 37 8 public int getwei 39 return to; ght( 63:49 İleMdf270NM Smart Insert ^%。 do ENG 16:32 모

my java_programs - Chegg QA/c/May_2018/DijkstraAlgorithm Test.java - Eclipse File Edit Source Refactor Navigate Search Project Run Window Help Quick Access! : е 曰Console DUltimateFri.. return weight; D TreeTest java DListNodejava DApplicantTe ByReferenceE" J SegregateNe.. D Graph EdgeTe A DijkstraAlg ,s 9- 40 41 42 448public String tostring) 45 return "From: "+fromt"tTo: "+tot"tWeight: tweight; 47 48 50 51 52 public class DijkstraAlgorithmTest 538 public static void main(String[) args) throws FileNotFoundException f File file-new File("dijkstraFile.txt);//input file Scanner obj-new Scanner(file);//scanner object to read data from file 56 58 59 60 61 HashSetcCharacter> uniqueVertices new HashSet<Character;/all unique vertices in map 62 char source- 'A'//source vertex char destination-'B//destination vertex ArrayList<GraphEdge> edges-new ArrayList<GraphEdge>;//1ist to hold all edges ArrayListくCharacter» alivertices-new ArrayList<Character»();//list to hold all vertices 64 65int numberOfVertisss-Integer.parseInt (obj.nextine)); hile(obj.hasNextline)) //while input file has lines left 69 String line-obj.nextLine); 70 String vertex[]-line.split( ");/split the line into source vertex, destination vertex and the weight 71 72 GraphEdge edge-new GraphEdge(vertex[o].charAt (a), vertex[1].chart) Integer.parseInt (vertex[2]));//create a new gcaphedge object from line data 73 dges.add(edge 75 if(luniqueVertices.contains(vertex[e].charAt (e))) 76 //if vertex not present in unique vertices map, add it in map and acraylist uniqueVertices.add(vertex[) charAt ()) allVertices.add(vertexre1.charAt (0) Smart Insert 163:49 ^%。 do ENG 16:32 모

my java_programs - Chegg QA/c/May_2018/DijkstraAlgorithm Test.java - Eclipse File Edit Source Refactor Navigate Search Project Run Window Help Quick Access|: 製な e Console DUltimateFri.. D TreeTest java u ListNodejava DApplicantTe.. DByReferenceE.. D segregateNe.. D GraphEdgeTe ADijkstraA9-ㄨ s 9- 79 80 81 82 83 84 85 B6 87 if(luniqueVertices.contains (vertex[1].charAt (e))) {//if vertex not present in unique vertices map, add it in map and errada uniqueVertices.add (vertex[1].charAt (0)) allVertices.add(vertex[i].charAt(e) 89 HashMap<Character, Integer distance-new HashMap<Character, Integer>); 90 91 92 93 94 95 96 97 for(Character ch: ollvertices) distance.put (ch, Integer.MAX VALUE);//add all vertices to distance map with initial distance as infinite i.e Integer.NAX VALUE distance.put (source, e);//source distance is 8, update in distance map 98 /comparator to arrange the vertices in the priority queue in min heap fashion 99Θ Comparator <Character» cmp-new Comparator<Characters() public int c ompare(Character a, Character b) 182 103 if(distance.get(a)<distance.get(b)) return -1; else if(distance.get (a) -distance.get 185 return 8 107 110 //create a priority queue PriorityQuhracter> pq-new PriorityQueue<Character> (cmp);//priority queuemio heap to arrange vertices in mio heap fashion for (Character ch: allvertices) 113 114 115 116 pq.add (ch);/Jadd all the vertices to Ra string path."";//hold the final path from a to b 150M ot 270M Smart Insert 163:49 do ENG 16:32 모 /\

my java_programs - Chegg QA/c/May_2018/DijkstraAlgorithm Test.java - Eclipse File Edit Source Refactor Navigate Search Project Run Window Help Quick Access|: l i E ! 製な е 曰Console DUltimateFri., DTreeTest java DListNodejava DApplicantTe ByReferenceE" J SegregateNe.. D Graph EdgeTe A DijkstraA9-ㄨ s 9- 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 while(Ipq.isEmpty)) //while there are elements in the pq char chepremove);//get the vertex path+-ch;//append the vertex to path if (ch--destination)//if reached destination break;/loop out List<GraphEdge> outVertex-getalloutgoingEdges (edges, ch); for (GraphEdge edge:outVertex) (//for cach seds in the outVertex list if(pq.contains (edge.getTo))) //if the destination vertex in the edge is present In the pq if (distance.get(ch)+edge-geteight)<distance.get (edge.getToO) (//if new distance is less than the old distance distance.put (edge.getTo), distance.get(ch)+edge.getheight))//put new distance //the below 2 lines are executed to update the priority queue after change to distance pq.remove (edge.getTo));//remove destination vertex of edge to pg pq.add (edge.getTo));//add destination vertex of edge to pq // solution file File output-new File("DijkstraSolution.txt") Printwriter pw-new Printhriter(output); pw.println(distance.get (destination));/print the minuium distance to destination to file pw.println(path)i//print the path to file //print a successful message to the console System.out.printin Successful!"); pw.flush);//flush the output to file pw.closerS:ficlose Dw of 270M Smart Insert 163:49 do ENG 16:32 모 /\

my java_programs - Chegg QA/c/May_2018/DijkstraAlgorithm Test.java - Eclipse File Edit Source Refactor Navigate Search Project Run Window Help Quick Access|: 製な e Console DUltimateFri.. D TreeTest java u ListNodejava DApplicantTe.. DByReferenceE.. D segregateNe.. D GraphEdgeTe ADijkstraA9-ㄨ s 9- 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 distance-put(edge.getTo), distance.get(ch)tedge-getweight));//put new distance //the below 2 lines are executed to update the priority queue after change to distance pq.remove(edge.getTo));//remove destination vertex of edge to pg pq.add(edge.getTo))//add destination vertex of edge to pg // solution file File output-new File("DijkstraSolution.txt") Printwriter pw-new Printhriter(output); pw.printin(distance.get (destination));//print the minuinum distance to destination to file pw.println(path);//print the path to file //print a successful message to the console System.out.println( "Successful!") pw.flush();//flush the output to file pw.close;//close pu obj.close();//close obǐ 60 //get all the outgoing edges in a list from the source yetctcx 61 public static List<GraphEdge> getAlloutgoingEdges (ArrayList<GraphEdge> list, char source) 162 63 List<GraphEdge> result-new ArrayList<GraphEdge>; 164 for (GraphEdge edge: list) 65 if(edge.getFrom)source) result.add (edge); 166 168 169 170 return result; 172 173 153 of 270M Smart Insert 163:49 155M of 270M do ENG 16:32 모 /\

INPUT FILE:

dijkstraFile-Notepad File Edit Format View Help he 2 ^ do ENG 16:25

OUTPUT FILE:

DijkstraSolution - Notepad File Edit Format View Help 142 AJGFEDHICB ^七.irido ENG 16:25 모

CONSOLE OUTPUT:

myjava-programs-Eclipse File Edit Navigate Search Project Run Window Help Quick Access 曰Console D UltimateFri.. D TreeTest java D ListNodejava D ByReferenceE.. ire1.8.0 171bin)javaw.exe (28-May-2018, 424:50 PM) D ApplicantTe.. D segregateNe.. D GraphEdgeTe D DijkstraAlg sw terminateds DijkstraAlgorithmTest Java Application] Successful! CProgram FilesJavaire1.8.0 15M of 2 ^ da ENG 16:24