241008 문자열 제곱

public static void main(String[] args) throws IOException {
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	String inputLine;

	while (true) {
		inputLine = br.readLine();
		if (inputLine.equals(".")) {
			break;
		}

		int maxRepetition = calculateMaxRepetition(inputLine);
		System.out.println(maxRepetition);
	}
}

private static int calculateMaxRepetition(String s) {
	char[] characters = s.toCharArray();
	int length = characters.length;
	int[] failure = buildFailureFunction(characters, length);

	int patternLength = length - failure[length - 1];
	if (patternLength == 0) {
		return 1;
	}
	return (length % patternLength == 0) ? (length / patternLength) : 1;
}

private static int[] buildFailureFunction(char[] characters, int length) {
	int[] failure = new int[length];
	failure[0] = 0;

	int currentIndex = 1;
	int prefixLength = 0;

	while (currentIndex < length) {
		if (characters[currentIndex] == characters[prefixLength]) {
			prefixLength++;
			failure[currentIndex] = prefixLength;
			currentIndex++;
		} else if (prefixLength > 0) {
			prefixLength = failure[prefixLength - 1];
		} else {
			failure[currentIndex] = 0;
			currentIndex++;
		}
	}

	return failure;
}

출처:https://www.acmicpc.net/problem/4354