import java.util.StringTokenizer; public class Solution2 extends Solution { public Solution2() { super(2); } public static void main(String[] args) { Solution2 solution = new Solution2(); solution.testPartTwo(); } private boolean hasRepeatedDigitsTwice(long number) { String s = String.valueOf(number); int n = s.length(); // must have even number of digits if (n % 2 != 0) return false; String left = s.substring(0, n / 2); String right = s.substring(n / 2); return left.equals(right); } @Override String solvePartOne(String inputData) { StringTokenizer sb = new StringTokenizer(inputData, ",\n"); long sum = 0; while (sb.hasMoreTokens()) { String token = sb.nextToken(); System.out.println(token); Long lowerBound = Long.parseLong(token.split("-")[0]); Long upperBound = Long.parseLong(token.split("-")[1]); System.out.println("In range: " + lowerBound + " to " + upperBound); for (long i = lowerBound; i <= upperBound; i++) { if (hasRepeatedDigitsTwice(i)) { System.out.println("+" + i); sum += i; } } } return Long.toString(sum); } private boolean hasRepeatedDigits(long number) { String s = String.valueOf(number); int n = s.length(); // Try every possible pattern length for (int len = 1; len <= n / 2; len++) { // total length must be divisible by pattern length if (n % len != 0) continue; String pattern = s.substring(0, len); int repeatCount = n / len; // Build repeated pattern StringBuilder sb = new StringBuilder(); for (int i = 0; i < repeatCount; i++) { sb.append(pattern); } // If equal and repeated at least twice then invalid if (sb.toString().equals(s) && repeatCount >= 2) { return true; } } return false; } @Override String solvePartTwo(String inputData) { StringTokenizer sb = new StringTokenizer(inputData, ",\n"); long sum = 0; while (sb.hasMoreTokens()) { String token = sb.nextToken(); System.out.println(token); Long lowerBound = Long.parseLong(token.split("-")[0]); Long upperBound = Long.parseLong(token.split("-")[1]); System.out.println("In range: " + lowerBound + " to " + upperBound); for (long i = lowerBound; i <= upperBound; i++) { if (hasRepeatedDigits(i)) { System.out.println("+" + i); sum += i; } } } return Long.toString(sum); } }