Graph Representation using Incidence Matrix in Java

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This is a java program to represent graph as a incidence list. The incidence matrix of G is a n × m matrix (b_{ij}), where n and m are the numbers of vertices and edges respectively, such that b_{ij} = 1 if the vertex v_i and edge x_j are incident and 0 otherwise.

Here is the source code of the Java Program to Represent Graph Using Incidence Matrix. The Java program is successfully compiled and run on a Windows system. The program output is also shown below.

  1. //This is a java program to represent graph as a incidence matrix
  2. import java.util.Scanner;
  3.  
  4. public class Represent_Graph_Incidence_Matrix 
  5. {
  6.     private final int rows;
  7.     private final int cols;
  8.     private int[][] incidence_matrix;
  9.  
  10.     public Represent_Graph_Incidence_Matrix(int v, int e) 
  11.     {
  12.         rows = v;
  13.         cols = e;
  14.         incidence_matrix = new int[rows + 1][cols + 1];
  15.     }
  16.  
  17.     public void makeEdge(int to, int from, int edge, int edge_number) 
  18.     {
  19.         try 
  20.         {
  21.             incidence_matrix[to][edge_number] = edge;
  22.             incidence_matrix[from][edge_number] = edge;
  23.         }
  24.         catch (ArrayIndexOutOfBoundsException index) 
  25.         {
  26.             System.out.println("The vertices does not exists");
  27.         }
  28.     }
  29.  
  30.     public int getEdge(int edge_number, int v) 
  31.     {
  32.         try 
  33.         {
  34.             return incidence_matrix[edge_number][v];
  35.         }
  36.         catch (ArrayIndexOutOfBoundsException index) 
  37.         {
  38.             System.out.println("The vertices does not exists");
  39.         }
  40.         return -1;
  41.     }
  42.  
  43.     public static void main(String args[]) 
  44.     {
  45.         int v, e, count = 1, to = 0, from = 0, edge_number;
  46.         Scanner sc = new Scanner(System.in);
  47.         Represent_Graph_Incidence_Matrix graph;
  48.         try 
  49.         {
  50.             System.out.println("Enter the number of vertices: ");
  51.             v = sc.nextInt();
  52.             System.out.println("Enter the number of edges: ");
  53.             e = sc.nextInt();
  54.  
  55.             graph = new Represent_Graph_Incidence_Matrix(v, e);
  56.  
  57.             System.out.println("Enter the edges: <edge_number> <to> <from>");
  58.             while (count <= e) 
  59.             {
  60.                 edge_number = sc.nextInt();
  61.                 to = sc.nextInt();
  62.                 from = sc.nextInt();
  63.  
  64.                 graph.makeEdge(to, from, 1, edge_number);
  65.                 count++;
  66.             }
  67.  
  68.             System.out.println("The incidence matrix for the given graph is: ");
  69.             System.out.print("  ");
  70.             for (int i = 1; i <= v; i++)
  71.                 System.out.print(i + " ");
  72.             System.out.println();
  73.  
  74.             for (int i = 1; i <= v; i++) 
  75.             {
  76.                 System.out.print(i + " ");
  77.                 for (int j = 1; j <= v; j++) 
  78.                     System.out.print(graph.getEdge(i, j) + " ");
  79.                 System.out.println();
  80.             }
  81.  
  82.         }
  83.         catch (Exception E) 
  84.         {
  85.             System.out.println("Somthing went wrong");
  86.         }
  87.  
  88.         sc.close();
  89.     }
  90.  
  91. }

Output:

$ javac Represent_Graph_Incidence_Matrix.java
$ java Represent_Graph_Incidence_Matrix
 
Enter the number of vertices: 
4 
Enter the number of edges: 
5
Enter the edges: <edge_number> <to> <from>
1 1 2
2 2 3
3 3 4 
4 4 1
1 1 3
The incidence matrix for the given graph is: 
  1 2 3 4 
1 1 0 0 1 
2 1 1 0 0 
3 1 1 1 0 
4 0 0 1 1

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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