98 lines
3.4 KiB
Java
98 lines
3.4 KiB
Java
/*This Java program,to perform the topological Sort on a given graph by the DFS method.The topological sort is performed on a directed acyclic graph.*/
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import java.util.InputMismatchException;
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import java.util.Scanner;
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import java.util.Stack;
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public class TopoCycle
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{
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private Stack<Integer> stack;
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public TopoCycle()
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{
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stack = new Stack<Integer>();
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}
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public boolean checkCycle(int adjacency_matrix[][], int source)
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{
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int number_of_nodes = adjacency_matrix[source].length - 1;
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int[] topological_sort = new int [number_of_nodes + 1];
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int pos = 1;
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int j;
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boolean cycle = false;
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int visited[] = new int[number_of_nodes + 1];
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int element = source;
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int i = source;
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visited[source] = 1;
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stack.push(source);
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while (!stack.isEmpty())
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{
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element = stack.peek();
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while (i <= number_of_nodes)
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{
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if (adjacency_matrix[element][i] == 1 && visited[i] == 1)
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{
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if (stack.contains(i))
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{
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System.out.println("The Graph Contains a cycle");
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cycle = true;
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return cycle;
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}
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}
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if (adjacency_matrix[element][i] == 1 && visited[i] == 0)
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{
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stack.push(i);
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visited[i] = 1;
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element = i;
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i = 1;
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continue;
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}
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i++;
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}
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j = stack.pop();
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topological_sort[pos++] = j;
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i = ++j;
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}
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System.out.println("The Graph does not Contain cycle");
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return cycle;
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}
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public static void main(String...arg)
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{
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int number_no_nodes, source;
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Scanner scanner = null;
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try
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{
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System.out.println("Enter the number of nodes in the graph");
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scanner = new Scanner(System.in);
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number_no_nodes = scanner.nextInt();
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int adjacency_matrix[][] = new int[number_no_nodes + 1][number_no_nodes + 1];
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System.out.println("Enter the adjacency matrix");
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for (int i = 1; i <= number_no_nodes; i++)
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for (int j = 1; j <= number_no_nodes; j++)
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adjacency_matrix[i][j] = scanner.nextInt();
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System.out.println("Enter the source for the graph");
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source = scanner.nextInt();
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TopoCycle topoCycle = new TopoCycle();
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topoCycle.checkCycle(adjacency_matrix, source);
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}
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catch(InputMismatchException inputMismatch)
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{
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System.out.println("Wrong Input format");
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}
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scanner.close();
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}
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}
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/*
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Enter the number of nodes in the graph
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5
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Enter the adjacency matrix
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0 1 0 1 0
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0 0 1 0 0
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0 0 0 0 1
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0 1 0 0 1
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0 0 0 1 0
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Enter the source for the graph
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1
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The Graph contains a cycle |