All the Borders — Solution & Editorial
The borders are exactly the chain π[n−1], π[π[n−1]−1], ... following failure links from the last position down to 0.
Complexity: O(|S|)
The borders are exactly the chain π[n−1], π[π[n−1]−1], ... following failure links from the last position down to 0.
Complexity: O(|S|)