2016: d08: ex2: add solution

2016/d08/ex2/ex2.py

@@ -0,0 +1,70 @@
+#!/usr/bin/env python
+
+import enum
+import itertools
+import sys
+from typing import NamedTuple
+
+
+class Point(NamedTuple):
+    x: int
+    y: int
+
+
+class Op(enum.StrEnum):
+    RECT = "rect"
+    ROTATE_ROW = "row"
+    ROTATE_COLUMN = "column"
+
+
+MAX_X, MAX_Y = 50, 6
+
+
+def solve(input: str) -> str:
+    def parse_line(input: str) -> tuple[Op, int, int]:
+        split_input = input.split()
+        if split_input[0] == "rect":
+            x, y = split_input[1].split("x")
+            return Op.RECT, int(x), int(y)
+        op = Op(split_input[1])
+        line_col, _, shift = split_input[-3:]
+        return op, int(line_col[2:]), int(shift)
+
+    def parse(input: str) -> list[tuple[Op, int, int]]:
+        return [parse_line(line) for line in input.splitlines()]
+
+    def display_message(instructions: list[tuple[Op, int, int]]) -> set[Point]:
+        screen: set[Point] = set()
+        for op, a, b in instructions:
+            match op:
+                case Op.RECT:
+                    for x, y in itertools.product(range(a), range(b)):
+                        screen.add(Point(x, y))
+                case Op.ROTATE_ROW:
+                    pixels = {p for p in screen if p.y == a}
+                    screen -= pixels
+                    screen.update(Point((x + b) % MAX_X, y) for x, y in pixels)
+                case Op.ROTATE_COLUMN:
+                    pixels = {p for p in screen if p.x == a}
+                    screen -= pixels
+                    screen.update(Point(x, (y + b) % MAX_Y) for x, y in pixels)
+        return screen
+
+    def display(pixels: set[Point]) -> str:
+        return "\n".join(
+            "".join("#" if Point(x, y) in pixels else " " for x in range(MAX_X))
+            for y in range(MAX_Y)
+        )
+
+    instructions = parse(input)
+    pixels = display_message(instructions)
+    return display(pixels)
+
+
+def main() -> None:
+    input = sys.stdin.read()
+    print(solve(input))
+
+
+if __name__ == "__main__":
+    main()