How to find repeating sequence of characters in a given array?

Question

My problem is to find the repeating sequence of characters in the given array. simply, to identify the pattern in which the characters are appearing.

Answer 1

Not sure how you define "efficiently". For easy/fast implementation you could do this in Java:

    private static String findSequence(String text) {
        Pattern pattern = Pattern.compile("(.+?)\\1+");
        Matcher matcher = pattern.matcher(text);
        return matcher.matches() ? matcher.group(1) : null;
    }

it tries to find the shortest string (.+?) that must be repeated at least once (\1+) to match the entire input text.