2025 02

Python/2025/02/main.py

@@ -0,0 +1,60 @@
+input = open("input", 'r')
+
+ranges = []
+
+for i, line in enumerate(input):
+    raw_ranges = line.rstrip().split(",")
+    for id_range in raw_ranges:
+        id_start, id_end = id_range.split("-")
+        ranges.append((id_start,id_end))
+
+# Part 1
+# invalid_ids = []
+# for start_id, end_id in ranges:
+#     start_id_length = len(start_id)
+#     greater_half = start_id[:start_id_length//2]
+#     lesser_half = start_id[start_id_length//2:]
+#     
+#     # Find the closest invalid_id
+#     if start_id_length % 2 != 0:
+#         greater_half = "1" + "0"*len(greater_half)
+#     elif int(greater_half) < int(lesser_half):
+#         greater_half = str(int(greater_half) + 1)
+#     halves = greater_half
+#
+#     while int(halves*2) <= int(end_id):
+#         invalid_ids.append(int(halves*2))
+#         halves = str(int(halves) + 1)
+#
+# print(sum(invalid_ids))
+
+# Part 1 & 2
+invalid_ids = set()
+invalid_ids_p1 = []
+for start_id, end_id in ranges:
+    init_start_id = start_id
+    for sections in range(2,len(end_id)+1):
+        start_id = init_start_id
+        # ensure sections divides start_id
+        while len(end_id) >= len(start_id) and len(start_id) % sections != 0:
+            start_id = "1" + "0"*len(start_id)
+        if len(end_id) < len(start_id):
+            continue
+        divide_length = len(start_id) // sections
+
+        # Check starting position
+        greatest_sect = start_id[:divide_length]
+        if int(greatest_sect*sections) >= int(start_id) and \
+                int(greatest_sect*sections) <= int(end_id):
+            invalid_ids.add(int(greatest_sect*sections))
+            if sections == 2: invalid_ids_p1.append(int(greatest_sect*sections))
+        greatest_sect = str(int(greatest_sect) + 1)
+
+        # Check all other invalid_ids
+        while int(greatest_sect*sections) <= int(end_id):
+            invalid_ids.add(int(greatest_sect*sections))
+            if sections == 2: invalid_ids_p1.append(int(greatest_sect*sections))
+            greatest_sect = str(int(greatest_sect) + 1)
+
+print(sum(invalid_ids_p1))
+print(sum(invalid_ids))