Free Response AB1, part c

HashMap and TreeMap with LibraryItem id as the key.

For HashMap the three complexities are all O(1)
For TreeMap the three complexities are all O(log n)

Students can get credit for complexities for incorrect data 
structure selections.
                       add      checkout       getHolder
unsorted ArrayList     O(1)       O(n)            O(n)
sorted ArrayList       O(n)       O(log n)        O(log n)

unsorted LinkedList    O(1)       O(n)            O(n)
sorted LinkedList      O(n)       O(n)            O(n)

HashSet                O(1)       O(n)            O(n)
TreeSet                O(log n)   O(n)            O(n)

Note: TreeSet could be made to work efficiently if an appropriate Comparator
were passed to the constructor. Since this version of TreeSet and Comparator
are not in the AP CS Java subset, this solution would not be expected.


