question: public static Set < Interval > mergeIntervalToSet ( Set < Interval > intervals , Interval intervalToMerge ) { LinkedHashSet < Interval > copyOfOriginalSet = new LinkedHashSet < > ( intervals ) ; copyOfOriginalSet . add ( intervalToMerge ) ; return mergeIntervalSet ( copyOfOriginalSet ) ; }
target:  Merge an interval into the given interval set.