104 lines
3.3 KiB
Java
104 lines
3.3 KiB
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.*/
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//This is a java program to represent graph as a incidence matrix
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import java.util.Scanner;
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public class Represent_Graph_Incidence_Matrix
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{
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private final int rows;
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private final int cols;
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private int[][] incidence_matrix;
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public Represent_Graph_Incidence_Matrix(int v, int e)
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{
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rows = v;
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cols = e;
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incidence_matrix = new int[rows + 1][cols + 1];
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}
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public void makeEdge(int to, int from, int edge, int edge_number)
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{
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try
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{
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incidence_matrix[to][edge_number] = edge;
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incidence_matrix[from][edge_number] = edge;
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}
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catch (ArrayIndexOutOfBoundsException index)
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{
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System.out.println("The vertices does not exists");
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}
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}
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public int getEdge(int edge_number, int v)
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{
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try
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{
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return incidence_matrix[edge_number][v];
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}
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catch (ArrayIndexOutOfBoundsException index)
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{
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System.out.println("The vertices does not exists");
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}
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return -1;
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}
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public static void main(String args[])
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{
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int v, e, count = 1, to = 0, from = 0, edge_number;
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Scanner sc = new Scanner(System.in);
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Represent_Graph_Incidence_Matrix graph;
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try
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{
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System.out.println("Enter the number of vertices: ");
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v = sc.nextInt();
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System.out.println("Enter the number of edges: ");
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e = sc.nextInt();
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graph = new Represent_Graph_Incidence_Matrix(v, e);
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System.out.println("Enter the edges: <edge_number> <to> <from>");
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while (count <= e)
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{
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edge_number = sc.nextInt();
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to = sc.nextInt();
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from = sc.nextInt();
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graph.makeEdge(to, from, 1, edge_number);
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count++;
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}
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System.out.println("The incidence matrix for the given graph is: ");
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System.out.print(" ");
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for (int i = 1; i <= v; i++)
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System.out.print(i + " ");
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System.out.println();
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for (int i = 1; i <= v; i++)
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{
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System.out.print(i + " ");
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for (int j = 1; j <= v; j++)
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System.out.print(graph.getEdge(i, j) + " ");
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System.out.println();
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}
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}
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catch (Exception E)
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{
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System.out.println("Somthing went wrong");
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}
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sc.close();
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}
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}
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/*
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Enter the number of vertices:
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4
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Enter the number of edges:
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5
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Enter the edges: <edge_number> <to> <from>
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1 1 2
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2 2 3
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3 3 4
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4 4 1
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1 1 3
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The incidence matrix for the given graph is:
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1 2 3 4
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1 1 0 0 1
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2 1 1 0 0
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3 1 1 1 0
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4 0 0 1 1
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