question: public static ArrayList < Object > pruneItemSets ( ArrayList < Object > toPrune , Hashtable < ItemSet , Integer > kMinusOne ) { ArrayList < Object > newVector = new ArrayList < Object > ( toPrune . size ( ) ) ; int help , j ; for ( int i = 0 ; i < toPrune . size ( ) ; i ++ ) { ItemSet current = ( ItemSet ) toPrune . get ( i ) ; for ( j = 0 ; j < current . m_items . length ; j ++ ) { if ( current . m_items [ j ] != - 1 ) { help = current . m_items [ j ] ; current . m_items [ j ] = - 1 ; if ( kMinusOne . get ( current ) == null ) { current . m_items [ j ] = help ; break ; } else { current . m_items [ j ] = help ; } } } if ( j == current . m_items . length ) { newVector . add ( current ) ; } } return newVector ; }
target:  Prunes a set of (k)-item sets using the given (k-1)-item sets.