question: public boolean compatible ( int begin , int end ) { if ( begin >= firstZero ) { BitSet pattern = new BitSet ( ) ; pattern . set ( begin - firstZero , end - firstZero ) ; return ! bits . intersects ( pattern ) ; } return false ; }
target:  Tests whether a new range is compatible with the current coverage vector. It must be after the first uncovered word, obviously, and must not conflict with spans after the first uncovered word.