2024 day 5 part 1 and 2

README.md

@@ -15,7 +15,7 @@
 - 2021 - ★★★★★ ★★★★★ ★★★★★ ★★★
 - 2022 - ★★★★★ ★★★★★ ★★★★★ ★☆
 - 2023 - ★★★★★ ★★★★★ ★★★★★ ★★★☆
-- 2024 - ★★★★
+- 2024 - ★★★★★
 
 ## How to use
 

src/year2024/day05a.py

@@ -0,0 +1,36 @@
+"""2024 - Day 5 Part 1: ..."""
+
+from collections import defaultdict
+
+
+def is_valid(update: list[int], rules: dict[int, set[int]]) -> bool:
+    for i in range(len(update) - 1):
+        a = update[i]
+        b = update[i + 1]
+
+        if b not in rules[a]:
+            return False
+
+    return True
+
+
+def solve(task: str) -> int:
+    first, second = task.split("\n\n")
+    rules: dict[int, set[int]] = defaultdict(set)
+
+    for line in first.split("\n"):
+        a, b = line.split("|")
+        rules[int(a)].add(int(b))
+
+    updates: list[list[int]] = []
+
+    for line in second.split("\n"):
+        updates.append([int(x) for x in line.split(",")])
+
+    ans = 0
+    for update in updates:
+        if is_valid(update, rules):
+            middle = update[len(update) // 2]
+            ans += middle
+
+    return ans

src/year2024/day05b.py

@@ -0,0 +1,44 @@
+"""2024 - Day 5 Part 2: ..."""
+
+import functools
+from collections import defaultdict
+
+
+def is_valid(update: list[int], rules: dict[int, set[int]]) -> bool:
+    for i in range(len(update) - 1):
+        a = update[i]
+        b = update[i + 1]
+
+        if b not in rules[a]:
+            return False
+
+    return True
+
+
+def solve(task: str) -> int:
+    first, second = task.split("\n\n")
+    rules: dict[int, set[int]] = defaultdict(set)
+
+    for line in first.split("\n"):
+        a, b = line.split("|")
+        rules[int(a)].add(int(b))
+
+    updates: list[list[int]] = []
+
+    def compare(x: int, y: int) -> int:
+        if y in rules[x]:
+            return -1
+        else:
+            return +1
+
+    for line in second.split("\n"):
+        updates.append([int(x) for x in line.split(",")])
+
+    ans = 0
+    for update in updates:
+        if not is_valid(update, rules):
+            update.sort(key=functools.cmp_to_key(compare))
+            middle = update[len(update) // 2]
+            ans += middle
+
+    return ans

tests/src/year2024/test_day05a.py

@@ -0,0 +1,41 @@
+"""2024 - Day 5 Part 1: ..."""
+
+from textwrap import dedent
+
+from src.year2024.day05a import solve
+
+
+def test_solve():
+    task = dedent(
+        """
+        47|53
+        97|13
+        97|61
+        97|47
+        75|29
+        61|13
+        75|53
+        29|13
+        97|29
+        53|29
+        61|53
+        97|53
+        61|29
+        47|13
+        75|47
+        97|75
+        47|61
+        75|61
+        47|29
+        75|13
+        53|13
+
+        75,47,61,53,29
+        97,61,53,29,13
+        75,29,13
+        75,97,47,61,53
+        61,13,29
+        97,13,75,29,47
+        """
+    ).strip()
+    assert solve(task) == 143

tests/src/year2024/test_day05b.py

@@ -0,0 +1,41 @@
+"""2024 - Day 5 Part 2: ..."""
+
+from textwrap import dedent
+
+from src.year2024.day05b import solve
+
+
+def test_solve():
+    task = dedent(
+        """
+        47|53
+        97|13
+        97|61
+        97|47
+        75|29
+        61|13
+        75|53
+        29|13
+        97|29
+        53|29
+        61|53
+        97|53
+        61|29
+        47|13
+        75|47
+        97|75
+        47|61
+        75|61
+        47|29
+        75|13
+        53|13
+
+        75,47,61,53,29
+        97,61,53,29,13
+        75,29,13
+        75,97,47,61,53
+        61,13,29
+        97,13,75,29,47
+        """
+    ).strip()
+    assert solve(task) == 123