text: var LinkedList = require('./../util/LinkedList');
  
  var loopDetection = (head) => {
    var hare = head;
    var tortoise = head;
    while (hare !== null) {
      tortoise = tortoise.next;
      hare = hare.next;
      if (hare === tortoise && hare !== head.next) {
        return true;
      }
      if (hare !== null) {
        hare = hare.next;
        if (hare === tortoise) {
          return true;
        }
      }
    }
    return false;
  };
  
  /* TEST */
  // A -> B -> C -> D -> E -> C
  
  var a = new LinkedList();
  var b = new LinkedList();
  var c = new LinkedList();
  var d = new LinkedList();
  var e = new LinkedList();
  var f = new LinkedList();
  
  a.next = b;
  b.next = c;
  c.next = d;
  d.next = e;
  e.next = f;
  f.next = c;
  
  console.log(loopDetection(a), true);
  
  var A = new LinkedList();
  var B = new LinkedList();
  var C = new LinkedList();
  var D = new LinkedList();
  var E = new LinkedList();
  var F = new LinkedList();
  
  A.next = B;
  B.next = C;
  C.next = D;
  D.next = E;
  E.next = F;
  
  console.log(loopDetection(A), false);
  