Day 5 solved

SimonBaars · SimonBaars · commit 13251a963ef8 · 2026-01-13T10:53:52.000-06:00
diff --git a/src/main/java/com/sbaars/adventofcode/year25/days/Day5.java b/src/main/java/com/sbaars/adventofcode/year25/days/Day5.java
@@ -0,0 +1,75 @@
+package com.sbaars.adventofcode.year25.days;
+
+import com.sbaars.adventofcode.year25.Day2025;
+import java.util.*;
+import java.util.stream.Collectors;
+
+public class Day5 extends Day2025 {
+  public Day5() {
+    super(5);
+  }
+
+  public static void main(String[] args) {
+    new Day5().printParts();
+  }
+
+  record Range(long start, long end) {
+    boolean contains(long id) {
+      return id >= start && id <= end;
+    }
+  }
+
+  @Override
+  public Object part1() {
+    String[] parts = day().split("\n\n");
+    
+    List<Range> ranges = Arrays.stream(parts[0].split("\n"))
+        .map(line -> {
+          String[] nums = line.split("-");
+          return new Range(Long.parseLong(nums[0]), Long.parseLong(nums[1]));
+        })
+        .collect(Collectors.toList());
+    
+    return Arrays.stream(parts[1].split("\n"))
+        .map(Long::parseLong)
+        .filter(id -> ranges.stream().anyMatch(range -> range.contains(id)))
+        .count();
+  }
+
+  @Override
+  public Object part2() {
+    String[] parts = day().split("\n\n");
+    
+    List<Range> ranges = Arrays.stream(parts[0].split("\n"))
+        .map(line -> {
+          String[] nums = line.split("-");
+          return new Range(Long.parseLong(nums[0]), Long.parseLong(nums[1]));
+        })
+        .collect(Collectors.toList());
+    
+    // Merge overlapping ranges and count total IDs
+    ranges.sort(Comparator.comparingLong(Range::start));
+    
+    long totalFresh = 0;
+    long currentStart = ranges.get(0).start;
+    long currentEnd = ranges.get(0).end;
+    
+    for (int i = 1; i < ranges.size(); i++) {
+      Range r = ranges.get(i);
+      if (r.start <= currentEnd + 1) {
+        // Overlapping or adjacent, merge
+        currentEnd = Math.max(currentEnd, r.end);
+      } else {
+        // Non-overlapping, count current range and start new one
+        totalFresh += (currentEnd - currentStart + 1);
+        currentStart = r.start;
+        currentEnd = r.end;
+      }
+    }
+    
+    // Add the last range
+    totalFresh += (currentEnd - currentStart + 1);
+    
+    return totalFresh;
+  }
+}
