141 has cycle

Added has cycle linked list question

Author: cheshtaaagarrwal

leetcode/java/linkedlist/141

@@ -0,0 +1,16 @@
+  public boolean hasCycle(final ListNode head) {
+        if (head == null || head.next == null)
+            return false;
+
+        ListNode slow = head;
+        ListNode fast = head;
+
+        while (fast != null && fast.next != null) {
+            slow = slow.next;
+            fast = fast.next.next;
+            if (slow == fast)
+                return true;
+        }
+
+        return false;
+    }