Can we count the number of inversions in time $\mathcal{O}(n)$?

Pergunta

It is possible to find the total number of inversions by $\mathcal{O}(n\log{}n)$ running time (extension of merge-sort algorithm for example).

Is there more asymptotically efficient way to do it? $\mathcal{O}(n)$? Or is there any proof that’s not possible?

Nenhuma solução correta