# Problem 63: Counting Factors by Length


Let $\fac_x[\ell]$ denote the number of (distinct) factors of length $\ell$ occurring in a word $x$.

Show how to compute in linear time all numbers $\fac_x[\ell]$, $\ell=1,\dots,|x|$, related to a word $x$, assuming a constant-size alphabet.
Exploit the Suffix tree of the word.