Function rustfst::algorithms::state_sort

pub fn state_sort<W, F>(fst: &mut F, order: &[StateId]) -> Result<()> where
    W: Semiring,
    F: MutableFst<W>, 

Sorts the input states of an FST. order[i] gives the the state ID after sorting that corresponds to the state ID i before sorting; it must therefore be a permutation of the input FST's states ID sequence.