Day 12 13

2021/13.py

@@ -0,0 +1,72 @@
+from dataclasses import dataclass
+
+
+@dataclass(frozen=True, eq=True)
+class Point:
+    x: int
+    y: int
+
+
+@dataclass
+class Fold:
+    axis: str
+    val: int
+
+
+def fold_grid(points: list[Point], fold: Fold) -> list[Point]:
+    """Apply fold transformation to points on the grid"""
+    points = points.copy()
+    for i, point in enumerate(points):
+        if fold.axis == "x" and point.x > fold.val:
+            points[i] = Point(x=2 * fold.val - point.x, y=point.y)
+        elif fold.axis == "y" and point.y > fold.val:
+            points[i] = Point(x=point.x, y=2 * fold.val - point.y)
+    return points
+
+
+def find_max_xy(points: list[Point]) -> tuple[int, int]:
+    """Find the maximum values for x and y on the current grid"""
+    return max(point.x for point in points), max(point.y for point in points)
+
+
+def print_grid(points: list[Point]) -> None:
+    """Print the current state of the grid"""
+    # get boundary coordinates for current grid
+    max_x, max_y = find_max_xy(points)
+    print(
+        "\n".join(
+            "".join("#" if Point(x, y) in points else "." for x in range(max_x + 1))
+            for y in range(max_y + 1)
+        )
+    )
+
+
+def part_1(points: list[Point], fold: Fold) -> int:
+    """calc number of visible dots after first fold"""
+    points = fold_grid(points, fold)
+    return len(set(points))
+
+
+def part_2(points: list[Point], folds: list[Fold]) -> None:
+    """print the final code"""
+    for fold in folds:
+        points = fold_grid(points, fold)
+    print_grid(points)
+
+
+if __name__ == "__main__":
+    with open("./2021/13.input", "r") as input:
+        points, folds = input.read().split("\n\n")
+        points = [
+            Point(*tuple(map(int, point.split(",")))) for point in points.splitlines()
+        ]
+        folds = [
+            Fold(*(axis[-1], int(val)))
+            for fold in folds.splitlines()
+            for axis, val in [fold.split("=")]
+        ]
+
+    part_1_ans = part_1(points, folds[0])
+    print(part_1_ans)
+
+    part_2(points, folds)