FUNCTION length(LIST list) : INT
// returns number of nodes until the end of the list

FUNCTION skip(LIST list, INT k) : LIST
// return the sublist of list, skipping k nodes

FUNCTION intersection(LIST list1, list2) : LIST
// returns the sublist where the two lists intersects
  INT n1 = length(list1);
  INT n2 = length(list2);

  IF (n1 > n2) THEN
     list1 = skip(list1, n1-n2)
  ELSE
     list2 = skip(list2, n2-n1)

  WHILE (list1 != list2)
    list1 = skip(list1, 1)
    list2 = skip(list2, 1)

  RETURN list1