2024 day 14.

src/holt59/aoc/2024/day14.py

@@ -1,7 +1,72 @@
+import itertools as it
+import operator as op
+from math import prod
 from typing import Any, Iterator
 
+import parse  # pyright: ignore[reportMissingTypeStubs]
+
 from ..base import BaseSolver
 
 
 class Solver(BaseSolver):
-    def solve(self, input: str) -> Iterator[Any]: ...
+    def solve(self, input: str) -> Iterator[Any]:
+        positions: list[tuple[int, int]] = []
+        velocities: list[tuple[int, int]] = []
+
+        for line in input.splitlines():
+            r = parse.parse("p={x:d},{y:d} v={vx:d},{vy:d}", line)  # type: ignore
+            positions.append((r["y"], r["x"]))  # type: ignore
+            velocities.append((r["vy"], r["vx"]))  # type: ignore
+
+        n_rows, n_cols = 103, 101
+        if len(positions) < 20:
+            n_rows, n_cols = 7, 11
+
+        n_rounds = 100
+        new_positions = [
+            ((row + v_row * n_rounds) % n_rows, (col + v_col * n_rounds) % n_cols)
+            for (row, col), (v_row, v_col) in zip(positions, velocities, strict=True)
+        ]
+
+        midrow = n_rows // 2
+        midcol = n_cols // 2
+
+        yield prod(
+            (
+                sum(opr(row, midrow) and opc(col, midcol) for row, col in new_positions)
+                for opr, opc in it.product((op.gt, op.lt), repeat=2)
+            )
+        )
+
+        new_positions = positions.copy()
+        for rnd in self.progress.wrap(range(10000)):
+            new_positions = [
+                ((row + v_row) % n_rows, (col + v_col) % n_cols)
+                for (row, col), (v_row, v_col) in zip(
+                    new_positions, velocities, strict=True
+                )
+            ]
+            m = [[False for _ in range(n_cols)] for _ in range(n_rows)]
+            for row, col in new_positions:
+                m[row][col] = True
+
+            found = False
+            for row in m:
+                if sum(row) <= 10:
+                    continue
+                if any(all(row[i : i + 10]) for i in range(n_cols - 10)):
+                    if self.files:
+                        self.files.create(
+                            f"result_{rnd+1}.txt",
+                            "\n".join(
+                                "".join("#" if m[i][j] else "." for j in range(n_cols))
+                                for i in range(n_rows)
+                            ).encode(),
+                            True,
+                        )
+                    yield rnd + 1
+                    found = True
+                    break
+
+            if found:
+                break