Day 2

src/main/java/de/advent_of_code_2025/two/Main.java

@@ -0,0 +1,122 @@
+package de.advent_of_code_2025.two;
+
+import de.advent_of_code_2025.util.InputMangler;
+import de.advent_of_code_2025.util.InputReader;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.LongStream;
+
+public class Main {
+    private static final record IdRange(Long start, Long end) {
+        public long sumDoubleSequence() {
+            return LongStream.range(start, end + 1).filter(IdRange::isDoubleSequence).sum();
+        }
+
+        public long sumAnySequence() {
+            return LongStream.range(start, end + 1).filter(IdRange::isAnySequence).sum();
+        }
+
+        private static boolean isAnySequence(long n) {
+            if(n < 10) {
+                return false;
+            }
+
+            final List<Long> digits = getDigits(n).reversed();
+            final String nString = String.valueOf(n);
+
+            if(allDigitsSame(nString, digits)) {
+                return true;
+            }
+
+            for(int i = 2; i < 6; i++) {
+                if(hasSequence(nString, digits, i)) {
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
+        private static final boolean allDigitsSame(String nString, List<Long> digits) {
+            return String.valueOf(digits.getFirst()).repeat(digits.size()).equals(nString);
+        }
+
+        private static final boolean hasSequence(String nString, List<Long> digits, int sequenceLength) {
+            if(sequenceLength >= digits.size()) {
+                return false;
+            }
+
+            return digits.subList(0, sequenceLength).stream().map(String::valueOf).collect(Collectors.joining()).repeat(digits.size() / sequenceLength).equals(nString);
+        }
+
+        private static boolean isDoubleSequence(long n) {
+            if(n < 10) {
+                return false;
+            }
+
+            final List<Long> digits = getDigits(n);
+
+            if(digits.size() % 2 > 0) { // odd digit numbers not relevant
+                return false;
+            }
+
+            List<Long> half = digits.subList(0, digits.size() / 2);
+
+            return digits.subList(digits.size() / 2, digits.size()).equals(half);
+        }
+
+        private static final List<Long> getDigits(long n) {
+            final List<Long> digits = new ArrayList<>();
+
+            long lastDigit = n % 10;
+
+            digits.add(lastDigit);
+
+            n = n / 10;
+
+            while (n > 0) {
+                lastDigit = n % 10;
+
+                digits.add(lastDigit);
+
+                n = n / 10;
+            }
+
+            return digits;
+        }
+    }
+
+    public static void main(String[] args) throws Throwable {
+        final String line = InputReader.readSingle(args);
+        final List<String> lines = InputMangler.mangleSingle(line, ",");
+        final List<IdRange> idRanges = setupRanges(lines);
+        long sameDigitSum = 0;
+        long anySequenceSum = 0;
+
+        // Part 1
+
+        for (IdRange range : idRanges) {
+            sameDigitSum += range.sumDoubleSequence();
+        }
+
+        System.out.println(sameDigitSum);
+
+        // Part 2
+
+        for (IdRange range : idRanges) {
+            anySequenceSum += range.sumAnySequence();
+        }
+
+        System.out.println(anySequenceSum);
+    }
+
+    private static final List<IdRange> setupRanges(List<String> lines) {
+        return lines.stream().map(line -> {
+            final String[] split = line.split("-");
+
+            return new IdRange(Long.parseLong(split[0]), Long.parseLong(split[1]));
+        }).collect(Collectors.toList());
+    }
+}

src/main/java/de/advent_of_code_2025/util/InputMangler.java

@@ -1,6 +1,7 @@
 package de.advent_of_code_2025.util;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 import java.util.function.Predicate;
 
@@ -27,4 +28,10 @@ public class InputMangler {
 
         return retVal;
     }
+
+    public static final List<String> mangleSingle(String input, String mangleString) {
+        final List<String> retVal = new ArrayList<>();
+
+        return Arrays.asList(input.split(mangleString));
+    }
 }

src/main/java/de/advent_of_code_2025/util/InputReader.java

@@ -10,4 +10,9 @@ public class InputReader {
         final String fileName = args[0];
         return Files.readAllLines(Paths.get(fileName));
     }
+
+    public static final String readSingle(String[] args) throws IOException {
+        final String fileName = args[0];
+        return Files.readAllLines(Paths.get(fileName)).get(0);
+    }
 }

src/main/resources/two/input.txt

@@ -0,0 +1 @@
+199617-254904,7682367-7856444,17408-29412,963327-1033194,938910234-938964425,3207382-3304990,41-84,61624-105999,1767652-1918117,492-749,85-138,140-312,2134671254-2134761843,2-23,3173-5046,16114461-16235585,3333262094-3333392446,779370-814446,26-40,322284296-322362264,6841-12127,290497-323377,33360-53373,823429-900127,17753097-17904108,841813413-841862326,518858-577234,654979-674741,773-1229,2981707238-2981748769,383534-468118,587535-654644,1531-2363

src/main/resources/two/input_example.txt

@@ -0,0 +1 @@
+11-22,95-115,998-1012,1188511880-1188511890,222220-222224,1698522-1698528,446443-446449,38593856-38593862,565653-565659,824824821-824824827,2121212118-2121212124