public <S, P> Nfa<S> filterUnambiguousPaths(Pda<S, P> pda) {
Map<S, List<S>> followers = Maps.newLinkedHashMap();
Map<S, Integer> distanceMap = nfaUtil.distanceToFinalStateMap(pda);
filterUnambiguousPaths(pda, pda.getStart(), distanceMap, followers);
return new NfaUtil.NFAImpl<S>(pda.getStart(), pda.getStop(), followers);
}
