/**
* Given an array of slices (potentially overlapping and in any order) and return an equivalent
* array of non-overlapping slices in clustering order.
*
* @param slices an array of slices. This may be modified by this method.
* @return the smallest possible array of non-overlapping slices in clustering order. If the
* original slices are already non-overlapping and in comparator order, this may or may not
* return the provided slices directly.
*/
private List<Slice> normalize(List<Slice> slices) {
if (slices.size() <= 1) return slices;
Collections.sort(
slices,
new Comparator<Slice>() {
@Override
public int compare(Slice s1, Slice s2) {
int c = comparator.compare(s1.start(), s2.start());
if (c != 0) return c;
return comparator.compare(s1.end(), s2.end());
}
});
List<Slice> slicesCopy = new ArrayList<>(slices.size());
Slice last = slices.get(0);
for (int i = 1; i < slices.size(); i++) {
Slice s2 = slices.get(i);
boolean includesStart = last.includes(comparator, s2.start());
boolean includesFinish = last.includes(comparator, s2.end());
if (includesStart && includesFinish) continue;
if (!includesStart && !includesFinish) {
slicesCopy.add(last);
last = s2;
continue;
}
if (includesStart) {
last = Slice.make(last.start(), s2.end());
continue;
}
assert !includesFinish;
}
slicesCopy.add(last);
return slicesCopy;
}
