Data Structures and Algorithms in Java[1].pdf - Fulvio Frisone

means of an unsorted or sorted list, respectively. We
assume that the list is implemented by a doubly linked
list. The space requirement is O(n).
Method
Unsorted List
Sorted List
size, isEmpty
O(1)
O(1)
insert
O(1)
O(n)
min, removeMin
O(n)
O(1)
Java Implementation
In Code Fragments 8.6 and 8.8, we show a Java implementation of a priority
queue based on a sorted node list. This implementation uses a nested class, called
MyEntry, to implement the Entry interface (see Section 6.5.1). We do not
show auxiliary method checkKey(k), which throws an
InvalidKeyException if key k cannot be compared with the comparator of
the priority queue. Class DefaultComparator, which realizes a comparator
using the natural ordering, is shown in Code Fragment 8.7.
Code Fragment 8.6: Portions of the Java class
SortedListPriorityQueue, which implements the
PriorityQueue interface. The nested class MyEntry
implements the Entry interface. (Continues in Code
Fragment 8.8.)
462