Given a length $N$ string $S$. Calculate the suffix array of $S$, $a_ i$.
$S$
$a_ 0$ $a_ 1$ ... $a_ {N-2}$ $a_ {N-1}$
abcbcba
6 0 5 3 1 4 2
mississippi
10 7 4 1 0 9 8 6 3 5 2
ababacaca
8 0 2 6 4 1 3 7 5
aaaaa
4 3 2 1 0
library checker: suffixarray