day 5

day-05/part-1.py

@@ -0,0 +1,18 @@
+import aocd
+
+def parse(data):
+    ranges, ids = map(lambda s: s.split('\n'), data.strip().split('\n\n'))
+    return [range(a, b+1) for a, b in (map(int, r.split('-')) for r in ranges)], map(int, ids)
+
+def is_fresh(ranges, id):
+    # This is acutally just fast in python
+    return any(id in r for r in ranges)
+
+def main(data):
+    ranges, ids = parse(data)
+    return sum(is_fresh(ranges, id) for id in ids)
+
+if __name__ == '__main__':
+    solution = main(aocd.get_data(day=5, year=2025))
+    print(solution)
+    aocd.submit(solution, part='a', day=5, year=2025)

day-05/part-2.py

@@ -0,0 +1,38 @@
+import aocd
+
+import math
+
+def parse(data):
+    return sorted(tuple(map(int, r.split('-'))) for r in data.split('\n\n')[0].strip().split('\n'))
+
+def merge_overlapping(ranges):
+    current_min = None
+    current_max = -math.inf
+
+    for new_min, new_max in ranges:
+        if new_min > current_max:
+            # Previous range is successfully merged
+            if current_min is not None:
+                # Previous range actually does exist
+                yield (current_min, current_max)
+            current_min = new_min
+            current_max = new_max
+        else:
+            # Need to merge current range into previous
+            # Use max() here to prevent (1, 10), (3, 7) from resolving to (1, 7), e.g.
+            current_max = max(new_max, current_max)
+    
+    # Get the range that gets missed at the end
+    yield (current_min, current_max)
+
+def range_length(low, high):
+    return high - low + 1
+
+def main(data):
+    ranges = parse(data)
+    return sum(range_length(*r) for r in merge_overlapping(ranges))
+
+if __name__ == '__main__':
+    solution = main(aocd.get_data(day=5, year=2025))
+    print(solution)
+    aocd.submit(solution, part='b', day=5, year=2025)