2025-2-2 (#22)

Author: jameslawlor

src/advent_of_code/year_2025/day_02.py

@@ -1,5 +1,6 @@
 from advent_of_code.utils.input_handling import read_input
 
+VALID_PARTS = (1,2)
 
 def parse_input(raw):
     raw_split = raw[0].split(",")
@@ -24,41 +25,62 @@ def check_id_valid(id):
     else:
         return True
 
-
-def get_invalid_ids_in_range(range_pair):
+def check_id_valid_v2(id):
+    id_len = len(str(id))
+    half_len = id_len // 2
+    for sub_str_len in range(1,half_len+1):
+        sub_str = id[:sub_str_len]
+        str_to_search = id[sub_str_len:]
+        if (len(str_to_search) % sub_str_len == 0): # substr divisible by search str length
+            if (sub_str * (id_len // sub_str_len) == id): # substr matches N * search string 
+                return False
+    return True
+
+def get_invalid_ids_in_range(range_pair, part):
     full_range = range(range_pair[0], range_pair[1] + 1)
+
+    if part == 1:
+        id_checker_function = check_id_valid
+    elif part == 2:
+        id_checker_function = check_id_valid_v2
+    else:
+        raise ValueError("Specify a valid part number")
+    
     invalid_ids = []
     for x in full_range:
-        if not check_id_valid(str(x)):
+        if not id_checker_function(str(x)):
             invalid_ids.append(x)
     return invalid_ids
 
 
-def find_invalid_ids_in_range_string(range_string):
+def find_invalid_ids_in_range_string(range_string, part):
     range_pair_as_ints = convert_range_string_to_pair(range_string)
-    invalid_ids_in_range = get_invalid_ids_in_range(range_pair_as_ints)
+    invalid_ids_in_range = get_invalid_ids_in_range(range_pair_as_ints, part)
     return invalid_ids_in_range
 
 
-def find_all_invalid_ids(parsed_input):
+def find_all_invalid_ids(parsed_input, part):
     invalid_ids = []
     for range_pair in parsed_input:
-        invalid_ids.extend(find_invalid_ids_in_range_string(range_pair))
+        invalid_ids.extend(find_invalid_ids_in_range_string(range_pair, part))
     return invalid_ids
 
 
 def sum_invalid_ids(invalid_ids):
     return sum(invalid_ids)
 
 
-def solve_part_1(parsed_input):
-    invalid_ids = find_all_invalid_ids(parsed_input)
+def solve_part(parsed_input, part):
+    invalid_ids = find_all_invalid_ids(parsed_input, part)
     return sum_invalid_ids(invalid_ids)
 
+def solve_part_2(parsed_input):
+    invalid_ids = find_all_invalid_ids(parsed_input)
+    return sum_invalid_ids(invalid_ids)
 
 def solve(parsed_input):
-    part_1_solution = solve_part_1(parsed_input)
-    part_2_solution = None
+    part_1_solution = solve_part(parsed_input, part=1)
+    part_2_solution = solve_part(parsed_input, part=2)
     return (part_1_solution, part_2_solution)
 
 

tests/year_2025/test_day_02.py

@@ -2,6 +2,7 @@
 
 from advent_of_code.year_2025.day_02 import (
     check_id_valid,
+    check_id_valid_v2,
     convert_range_string_to_pair,
     find_invalid_ids_in_range_string,
     parse_input,
@@ -17,7 +18,7 @@
             [
                 "11-22,95-115,998-1012,1188511880-1188511890,222220-222224,1698522-1698528,446443-446449,38593856-38593862,565653-565659,824824821-824824827,2121212118-2121212124"  # noqa: E501
             ],
-            (1227775554, None),
+            (1227775554, 4174379265),
         ],
     ],
 )
@@ -28,6 +29,36 @@ def test_solver(input, expected_output):
     result = solve(input_parsed)
     assert result == expected_output
 
+# 11-22 still has two invalid IDs, 11 and 22.
+# 95-115 now has two invalid IDs, 99 and 111.
+# 998-1012 now has two invalid IDs, 999 and 1010.
+# 1188511880-1188511890 still has one invalid ID, 1188511885.
+# 222220-222224 still has one invalid ID, 222222.
+# 1698522-1698528 still contains no invalid IDs.
+# 446443-446449 still has one invalid ID, 446446.
+# 38593856-38593862 still has one invalid ID, 38593859.
+# 565653-565659 now has one invalid ID, 565656.
+# 824824821-824824827 now has one invalid ID, 824824824.
+# 2121212118-2121212124 now has one invalid ID, 2121212121.
+
+@pytest.mark.parametrize(
+    "input, expected_invalid_ids",
+    [
+        ["11-22", [11, 22]],
+        ["95-115", [99, 111]],
+        ["998-1012", [999, 1010]],
+        ["1188511880-1188511890", [1188511885]],
+        ["222220-222224", [222222]],
+        ["1698522-1698528", []],
+        ["446443-446449", [446446]],
+        ["38593856-38593862", [38593859]],
+        ["565653-565659", [565656]],
+        ["824824821-824824827", [824824824]],
+        ["2121212118-2121212124", [2121212121]],
+    ],
+)
+def test_find_invalid_ids_in_range_string_part_2(input, expected_invalid_ids):
+    assert expected_invalid_ids == find_invalid_ids_in_range_string(input, part=2)
 
 @pytest.mark.parametrize(
     "input, expected_invalid_ids",
@@ -46,7 +77,7 @@ def test_solver(input, expected_output):
     ],
 )
 def test_find_invalid_ids_in_range_string(input, expected_invalid_ids):
-    assert expected_invalid_ids == find_invalid_ids_in_range_string(input)
+    assert expected_invalid_ids == find_invalid_ids_in_range_string(input, part=1)
 
 
 @pytest.mark.parametrize(
@@ -74,7 +105,22 @@ def test_convert_range_string_to_pair(input, expected_pair):
 
 @pytest.mark.parametrize(
     "input, is_valid",
-    [("11", False), ("12", True), ("22", False), ("998", True), ("1010", False)],
+    [("11", False), ("12", True), ("22", False), ("998", True), ("999", True), ("1010", False), ("565656", True)],
 )
 def test_check_id_valid(input, is_valid):
     assert is_valid == check_id_valid(input)
+
+@pytest.mark.parametrize(
+    "input, is_valid",
+    [
+        ("11", False), 
+        ("12", True), 
+        ("22", False), 
+        ("998", True), 
+        ("999", False), 
+        ("1010", False),
+        ("565656", False),
+    ],
+)
+def test_check_id_valid_v2(input, is_valid):
+    assert is_valid == check_id_valid_v2(input)