Write an algorithm to detect a cycle in a linked list

linked_list_cycle

// Assume a linked list object with mHead, and mTail LLNodes, and mSize for size of list

// If there is a cycle, the linked list would never break out of a while loop.
// So if it exceeds the length of the list, we know there's a cycle somewhere

bool isCycle() {
  if(mHead == NULL) return false;
  node * n = mHead;
  int lSize = mSize;
  while(true) {
    if (n->next == NULL) return false;
    if(lSize == -1) return true;
    lSize--;
  } 
}