Day 13

13/13.py

@@ -1,4 +1,72 @@
+import sys
 import numpy as np
+import re
+
+np.set_printoptions(threshold=sys.maxsize, linewidth=1000)
+
+
+def print_sheet(grid):
+    print(
+        str(grid)
+        .replace("False", ".")
+        .replace("True", "#")
+        .replace("[", "")
+        .replace("]", "")
+        .replace(" ", "")
+    )
+
+
+def part_one(points: np.ndarray, folds: list[tuple[str, int]], part_one=True):
+    x_max = folds[0][1] * 2 if folds[0][0] == "x" else folds[1][1] * 2
+    y_max = folds[0][1] * 2 if folds[0][0] == "y" else folds[1][1] * 2
+
+    grid = np.full((y_max + 1, x_max + 1), False)
+
+    grid[tuple(points.T)] = True
+
+    if part_one:
+        grid = do_fold(grid, folds[0])
+        return np.count_nonzero(grid)
+
+    for fold in folds:
+        grid = do_fold(grid, fold)
+
+    print_sheet(grid)
+
+
+def do_fold(grid: np.ndarray, fold: tuple[str, int]) -> np.ndarray:
+    if fold[0] == "x":
+        grid = grid.T
+
+    top_part = grid[: fold[1]]
+
+    bottom_part = grid[fold[1] + 1 :][::-1]
+
+    grid = top_part | bottom_part
+
+    if fold[0] == "x":
+        grid = grid.T
+
+    return grid
+
 
 if __name__ == "__main__":
-    pass
+    points_lst = []
+
+    while (line := sys.stdin.readline()) != "\n":
+        points_lst.append(tuple([int(x) for x in line.split(",")][::-1]))
+
+    points = np.array(points_lst)
+
+    folds = []
+
+    fold_line = re.compile(r"fold along ([xy])=(\d*)")
+
+    for line in sys.stdin.readlines():
+        match = fold_line.match(line)
+        folds.append((match.groups()[0], int(match.groups()[1])))
+
+    print("Part one:", part_one(points, folds))
+
+    print("Part two:")
+    part_one(points, folds, part_one=False)