import java.util.InputMismatchException; import java.util.Scanner; import java.util.Stack; public class CheckCycle { private Stack stack; private int adjacencyMatrix[][]; public CheckCycle() { stack = new Stack(); } public void dfs(int adjacency_matrix[][], int source) { int number_of_nodes = adjacency_matrix[source].length - 1; adjacencyMatrix = new int[number_of_nodes + 1][number_of_nodes + 1]; for (int sourcevertex = 1; sourcevertex <= number_of_nodes; sourcevertex++) { for (int destinationvertex = 1; destinationvertex <= number_of_nodes; destinationvertex++) { adjacencyMatrix[sourcevertex][destinationvertex] = adjacency_matrix[sourcevertex][destinationvertex]; } } int visited[] = new int[number_of_nodes + 1]; int element = source; int destination = source; visited[source] = 1; stack.push(source); while (!stack.isEmpty()) { element = stack.peek(); destination = element; while (destination <= number_of_nodes) { if (adjacencyMatrix[element][destination] == 1 && visited[destination] == 1) { if (stack.contains(destination)) { System.out.println("The Graph contains cycle"); return; } } if (adjacencyMatrix[element][destination] == 1 && visited[destination] == 0) { stack.push(destination); visited[destination] = 1; adjacencyMatrix[element][destination] = 0; element = destination; destination = 1; continue; } destination++; } stack.pop(); } } public static void main(String...arg) { int number_of_nodes, source; Scanner scanner = null; try { System.out.println("Enter the number of nodes in the graph"); scanner = new Scanner(System.in); number_of_nodes = scanner.nextInt(); int adjacency_matrix[][] = new int[number_of_nodes + 1][number_of_nodes + 1]; System.out.println("Enter the adjacency matrix"); for (int i = 1; i <= number_of_nodes; i++) for (int j = 1; j <= number_of_nodes; j++) adjacency_matrix[i][j] = scanner.nextInt(); System.out.println("Enter the source for the graph"); source = scanner.nextInt(); CheckCycle checkCycle = new CheckCycle(); checkCycle.dfs(adjacency_matrix, source); } catch(InputMismatchException inputMismatch) { System.out.println("Wrong Input format"); } scanner.close(); } } /* Enter the number of nodes in the graph 5 Enter the adjacency matrix 0 0 0 1 0 1 0 1 0 0 0 0 0 0 0 0 1 0 0 1 0 0 1 0 0 Enter the source for the graph 1 The Graph contains a cycle