Implement an algorithm to determine if a string has all unique characters. Whatif you cannot use additional data structures?

CC150-1.1.java

public boolean uniqueChar(String s) {
	if (s == null)
		throw new IllegalArgumentException();
	if (s.length() <= 1)
		return true;

	if (s.length() > 256)
		return false;
	boolean[] iFlag = new boolean[256];
	for (int i = 0; i < s.length(); i++) {
		if (iFlag[s.charAt(i)]) {
			return false;
		}
		iFlag[s.charAt(i)] = true;
	}
	return true;
}