/* Given a string, consider the prefix string made of the first N chars of * the string. Does that prefix string appear somewhere else in the string? * Assume that the string is not empty and that N is in the range * 1..str.length(). */ public boolean prefixAgain(String str, int n) { String prefix = str.substring(0, n); for(int i = n; i <= str.length() - n; i++) { if(str.substring(i, i + n).equals(prefix)) return true; } return false; }