Create LoopDetection.java

Author: harshithasudhakar

Linked List/Singly Linked List/LoopDetection.java

@@ -0,0 +1,40 @@
+/* Node is defined as
+
+class Node
+{
+    int data;
+    Node next;
+    Node(int d) {data = d; next = null; }
+}
+
+*/
+
+class LoopDetection {
+    public static Node detectCycle(Node head){
+        
+        Node meetingpoint = pointerMeet(head);
+        Node slow = meetingpoint;
+        Node fast = head;
+        
+        while(fast!=slow){
+            fast = fast.next;
+            slow = slow.next;
+        }
+        
+        return slow;
+    }
+    static Node pointerMeet(Node head){
+        
+        Node slow = head;
+        Node fast = head;
+        
+        while(fast!=null && fast.next!=null){
+            slow = slow.next;
+            fast = fast.next.next;
+            if(slow == fast){
+                return slow;
+            }
+        }
+        return null;
+    }
+}