O(nlogn) Algorithm - Find three evenly spaced ones within binary string

Question

I had this question on an Algorithms test yesterday, and I can\'t figure out the answer. It is driving me absolutely crazy, because it was worth about 40 points. I figure

Answer 1

An adaptation of the Rabin-Karp algorithm could be possible for you. Its complexity is 0(n) so it could help you.

Take a look http://en.wikipedia.org/wiki/Rabin-Karp_string_search_algorithm