How to find the number of lexicographically minimal string rotation?
For example:
S = abab, N = 2 S = abca, N = 1 S = aaaa, N = 4
I tried Duval's algorithm, it works very long. The string length of 100000000 characters.
Easy -- just determine the minimum period of the string. A string which is periodic in minimal period K will produce identical (and hence lexicographically equal) strings for exactly N/K different rotations, so whatever the lexicographic minimum is, it'll be the result of N/K different rotations.
来源：https://stackoverflow.com/questions/21026091/how-to-find-the-number-of-the-lexicographically-minimal-string-rotation