A list contains twenty integers, not necessarily distinct. Does the list contain at least two consecutive integers?
(1) If any single value in the list is increased by 1, the number of different values in the list does not change.
(2) At least one value occurs more than once in the list.
(1) If any single value in the list is increased by 1, the number of different values in the list does not change.
(2) At least one value occurs more than once in the list.
