Solution to problem 8 part 1 in Python

src/Year_2016/P8.py

@@ -1,53 +1,111 @@
-import numpy as np
+# --- Day 8: Two-Factor Authentication ---
 
-with open("files/test") as f:
+# You come across a door implementing what you can only assume is an
+# implementation of two-factor authentication after a long game of
+# requirements telephone.
+
+# To get past the door, you first swipe a keycard (no problem; there was one on
+# a nearby desk). Then, it displays a code on a little screen, and you type
+# that code on a keypad. Then, presumably, the door unlocks.
+
+# Unfortunately, the screen has been smashed. After a few minutes, you've taken
+# everything apart and figured out how it works. Now you just have to work out
+# what the screen would have displayed.
+
+# The magnetic strip on the card you swiped encodes a series of instructions
+# for the screen; these instructions are your puzzle input. The screen is 50
+# pixels wide and 6 pixels tall, all of which start off, and is capable of
+# three somewhat peculiar operations:
+
+#     rect AxB turns on all of the pixels in a rectangle at the top-left of the
+# screen which is A wide and B tall.
+#     rotate row y=A by B shifts all of the pixels in row A (0 is the top row)
+# right by B pixels. Pixels that would fall off the right end appear at the
+# left end of the row.
+#     rotate column x=A by B shifts all of the pixels in column A (0 is the
+# left column) down by B pixels. Pixels that would fall off the bottom appear
+# at the top of the column.
+
+# For example, here is a simple sequence on a smaller screen:
+
+#     rect 3x2 creates a small rectangle in the top-left corner:
+
+#     ###....
+#     ###....
+#     .......
+
+#     rotate column x=1 by 1 rotates the second column down by one pixel:
+
+#     #.#....
+#     ###....
+#     .#.....
+
+#     rotate row y=0 by 4 rotates the top row right by four pixels:
+
+#     ....#.#
+#     ###....
+#     .#.....
+
+#     rotate column x=1 by 1 again rotates the second column down by one pixel,
+# causing the bottom pixel to wrap back to the top:
+
+#     .#..#.#
+#     #.#....
+#     .#.....
+
+# As you can see, this display technology is extremely powerful, and will soon
+# dominate the tiny-code-displaying-screen market. That's what the
+# advertisement on the back of the display tries to convince you, anyway.
+
+# There seems to be an intermediate check of the voltage used by the display:
+# after you swipe your card, if the screen did work, how many pixels should be
+# lit?
+
+import numpy as np
+import numpy.typing as npt
+
+with open("files/P8.txt") as f:
     instructions = [line for line in f.read().strip().split("\n")]
 
-print(instructions)
 
-# grid = np.zeros((6,50), dtype=int)
-init_grid = np.zeros((3, 7), dtype=int)
-
-# initialize grid
-print(init_grid)
+def rect(instruction: str, grid: npt.NDArray[int]) -> npt.NDArray[int]:
+    _, row = instruction.split("x")
+    _, col = _.split()
+    grid[: int(row), : int(col)] = 1
 
 
-def rect(instruction, grid):
-    col, row = int(instruction[5:6]), int(instruction[7:])
-    # print(col,row)
-    grid[:row, :col] = 1
+def rotate_column(
+    instruction: str, grid: npt.NDArray[int]
+) -> npt.NDArray[int]:
+    _, cols = instruction.split("=")
+    x, _, steps = cols.split()
+    new_col = np.roll(grid[:, int(x) : int(x) + 1], int(steps), axis=0)
+    grid[:, int(x) : int(x) + 1] = new_col
 
 
-rect(instructions[0], init_grid)
-
-print(init_grid)
+def rotate_row(instruction: str, grid: npt.NDArray[int]) -> npt.NDArray[int]:
+    _, rows = instruction.split("=")
+    y, _, steps = rows.split()
+    new_row = np.roll(grid[int(y) : int(y) + 1, :], int(steps), axis=1)
+    grid[int(y) : int(y) + 1, :] = new_row
 
 
-def rotate_column(instruction, grid):
-    x, steps = int(instruction[16:17]), int(instruction[21:])
-    # print(x, steps)
-    new_col = np.roll(grid[:, x : x + 1], steps, axis=0)
-    grid[:, x : x + 1] = new_col
+def part_1() -> None:
+    # dimensions given by the problem
+    init_grid = np.zeros((6, 50), dtype=int)
+
+    for instruction in instructions:
+        if instruction.startswith("rect"):
+            rect(instruction, init_grid)
+        elif instruction.startswith("rotate row"):
+            rotate_row(instruction, init_grid)
+        elif instruction.startswith("rotate column"):
+            rotate_column(instruction, init_grid)
+
+    lit = np.sum(init_grid)
+
+    print(f"There should be {lit} pixels lit")
 
 
-rotate_column(instructions[1], init_grid)
-
-print(init_grid)
-
-
-def rotate_row(instruction, grid):
-    y, steps = int(instruction[13:14]), int(instruction[18:])
-    # print(y, steps)
-    new_row = np.roll(grid[y : y + 1, :], steps, axis=1)
-    grid[y : y + 1, :] = new_row
-
-
-rotate_row(instructions[2], init_grid)
-
-print(init_grid)
-
-rotate_column(instructions[3], init_grid)
-
-print(init_grid)
-
-print(np.sum(init_grid))
+if __name__ == "__main__":
+    part_1()