// forAll r1,r2 element differences: r1.rightStart()<r2.rightStart() -> r1.rightEnd()<r2.rightStart
ArrayList<Integer> regions = new ArrayList<Integer>();
for (int i = 0; i < differences.length; i++) {
RangeDifference curr = differences[i];
if (curr.kind() == RangeDifference.CHANGE && curr.rightLength() > 0) {
int startLine = curr.rightStart();
int endLine = curr.rightEnd() - 1;
if (startLine == endLine) {
regions.add(startLine);