Peek at next element in a Tree set using an iterator

Question

I was wondering if there was a way to accomplish this, or if there are alternative data structures. It has to be sorted, without duplicates, and have an iterator.

Answer 1

TreeSet has an iterator, is sorted, won't have duplicates, and is able to see the next higher element by using higher.

For example:

TreeSet<Integer> ts = new TreeSet<Integer>();
ts.add(1);
ts.add(4);
ts.add(4);
ts.add(3);

for (Integer i : ts) {
  System.out.println("current: " + i + " next:  " + ts.higher(i));
}

The output is:

current: 1  next: 3
current: 3  next: 4
current: 4  next: null