Merge pull request #589 from shivg7706/cycle

all cycles present in a graph

DataStructures/Graphs/Cycles.java

@@ -0,0 +1,89 @@
+import java.util.Scanner;
+import java.util.ArrayList;
+
+
+class Cycle {
+
+    private int nodes, edges;
+    private int [][] adjacencyMatrix;
+    private boolean [] visited;
+    ArrayList<ArrayList<Integer>> cycles = new ArrayList<ArrayList<Integer>>();
+    private  boolean [] finalCycles;
+
+    public Cycle() {
+        Scanner in = new Scanner(System.in);
+        System.out.print("Enter the no. of nodes: ");
+        nodes = in.nextInt();
+        System.out.print("Enter the no. of Edges: ");
+        edges = in.nextInt();
+
+        adjacencyMatrix = new int [nodes][nodes];
+        visited = new boolean [nodes];
+
+        for (int i = 0; i < nodes; i++) {
+            visited[i] = false;
+        }
+
+        System.out.println("Enter the details of each edges <Start Node> <End Node>");
+
+        for(int i = 0; i < edges; i++) {            
+            int start, end;
+            start = in.nextInt();
+            end = in.nextInt();
+            adjacencyMatrix[start][end] = 1;
+        }
+
+    }
+
+    public void start() {
+        for (int i = 0; i < nodes; i++) {
+            ArrayList<Integer> temp = new ArrayList<>();
+            dfs(i, i, temp);
+            for (int j = 0; j < nodes; j++) {
+                adjacencyMatrix[i][j] = 0;
+                adjacencyMatrix[j][i] = 0;
+            }
+        }
+    }
+
+    private void dfs(Integer start, Integer curr, ArrayList<Integer> temp) {
+        temp.add(curr);
+        visited[curr] = true;
+        for (int i = 0; i < nodes; i++) {
+            if(adjacencyMatrix[curr][i] == 1) {
+                if (i == start) {
+                    cycles.add(new ArrayList<Integer>(temp));
+                } else {
+                    if (!visited[i]) {
+                        dfs(start, i, temp);
+                    }
+                }
+            }
+        }
+
+        if(temp.size() > 0) {
+            temp.remove(temp.size() - 1);
+        }
+        visited[curr] = false;
+    }
+
+    public void printAll() {
+        for (int i = 0; i < cycles.size(); i++) {
+            for (int j = 0; j < cycles.get(i).size(); j++) {
+                System.out.print(cycles.get(i).get(j) + " -> ");
+            }
+            System.out.println(cycles.get(i).get(0));
+            System.out.println();
+        }
+
+    }
+
+}
+
+public class Cycles {
+    public static void main(String[] args) {
+        Cycle c = new Cycle();
+        c.start();
+        c.printAll();
+    }
+}