Find the smallest period of input string in O(n)?

Question

Given the following problem :

Definition :

Let S be a string over alphabet Σ .S\' is the smallest period of S

Answer 1

See if this solution works for O(n). I used rotation of strings.

public static int stringPeriod(String s){

    String s1= s;
    String s2= s1;

    for (int i=1; i 

The complete program is available in this github repository