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

@@ -1,4 +1,4 @@
-"""2024 - Day 5 Part 1: ..."""
+"""2024 - Day 5 Part 1: Print Queue"""
 
 from collections import defaultdict
 

src/year2024/day05b.py

@@ -1,4 +1,4 @@
-"""2024 - Day 5 Part 2: ..."""
+"""2024 - Day 5 Part 2: Print Queue"""
 
 import functools
 from collections import defaultdict

src/year2024/day06a.py

@@ -0,0 +1,63 @@
+"""2024 - Day 6 Part 1: Guard Gallivant"""
+
+SHIFTS = {
+    # r c
+    "^": (-1, 0),
+    ">": (0, +1),
+    "v": (+1, 0),
+    "<": (0, -1),
+}
+
+TURN = {
+    "^": ">",
+    ">": "v",
+    "v": "<",
+    "<": "^",
+}
+
+
+def find_guard(data: list[list[str]]) -> tuple[int, int]:
+    rows = len(data)
+    cols = len(data[0])
+
+    for r in range(rows):
+        for c in range(cols):
+            if data[r][c] == "^":
+                return r, c
+
+    raise ValueError
+
+
+def solve(task: str) -> int:
+    data = [list(line) for line in task.split("\n")]
+
+    gr, gc = find_guard(data)
+
+    rows = len(data)
+    cols = len(data[0])
+
+    visited = {(gr, gc)}
+
+    while True:
+        guard = data[gr][gc]
+
+        dr, dc = SHIFTS[guard]
+
+        nr = gr + dr
+        nc = gc + dc
+
+        if not (0 <= nr < rows and 0 <= nc < cols):
+            break  # out of border
+
+        if data[nr][nc] != "#":
+            data[nr][nc] = guard
+
+            gr = nr
+            gc = nc
+        else:
+            new_guard = TURN[guard]
+            data[gr][gc] = new_guard
+
+        visited.add((gr, gc))
+
+    return len(visited)

src/year2024/day06b.py

@@ -0,0 +1,65 @@
+"""2024 - Day 6 Part 2: Guard Gallivant"""
+
+from src.year2024.day06a import SHIFTS
+from src.year2024.day06a import TURN
+from src.year2024.day06a import find_guard
+
+
+def is_paradox(gr: int, gc: int, data: list[list[str]]) -> bool:
+    rows = len(data)
+    cols = len(data[0])
+
+    visited: set[tuple[str, int, int]] = set()
+
+    while True:
+        guard = data[gr][gc]
+
+        if (guard, gr, gc) in visited:
+            return True
+
+        visited.add((guard, gr, gc))
+
+        dr, dc = SHIFTS[guard]
+
+        nr = gr + dr
+        nc = gc + dc
+
+        if not (0 <= nr < rows and 0 <= nc < cols):
+            data[gr][gc] = "."
+            return False  # out of border
+
+        if data[nr][nc] not in {"#", "O"}:
+            data[gr][gc] = "."
+            data[nr][nc] = guard
+
+            gr = nr
+            gc = nc
+        else:
+            new_guard = TURN[guard]
+            data[gr][gc] = new_guard
+
+
+def solve(task: str) -> int:
+    data = [list(line) for line in task.split("\n")]
+
+    gr, gc = find_guard(data)
+
+    rows = len(data)
+    cols = len(data[0])
+
+    count = 0
+
+    for r in range(rows):
+        for c in range(cols):
+            if data[r][c] == "#" or (r, c) == (gr, gc):
+                continue
+
+            data[r][c] = "O"
+            data[gr][gc] = "^"
+
+            if is_paradox(gr, gc, data):
+                count += 1
+
+            data[r][c] = "."
+
+    return count

tests/src/year2024/test_day05a.py

@@ -1,4 +1,4 @@
-"""2024 - Day 5 Part 1: ..."""
+"""2024 - Day 5 Part 1: Print Queue"""
 
 from textwrap import dedent
 

tests/src/year2024/test_day05b.py

@@ -1,4 +1,4 @@
-"""2024 - Day 5 Part 2: ..."""
+"""2024 - Day 5 Part 2: Print Queue"""
 
 from textwrap import dedent
 

tests/src/year2024/test_day06a.py

@@ -0,0 +1,23 @@
+"""2024 - Day 6 Part 1: Guard Gallivant"""
+
+from textwrap import dedent
+
+from src.year2024.day06a import solve
+
+
+def test_solve():
+    task = dedent(
+        """
+        ....#.....
+        .........#
+        ..........
+        ..#.......
+        .......#..
+        ..........
+        .#..^.....
+        ........#.
+        #.........
+        ......#...
+        """
+    ).strip()
+    assert solve(task) == 41

tests/src/year2024/test_day06b.py

@@ -0,0 +1,23 @@
+"""2024 - Day 6 Part 2: Guard Gallivant"""
+
+from textwrap import dedent
+
+from src.year2024.day06b import solve
+
+
+def test_solve():
+    task = dedent(
+        """
+        ....#.....
+        .........#
+        ..........
+        ..#.......
+        .......#..
+        ..........
+        .#..^.....
+        ........#.
+        #.........
+        ......#...
+        """
+    ).strip()
+    assert solve(task) == 6